There have been a few requests for this over the last few weeks, so I updated an older article and added some tips at the end.  I am sure I missed a few things here and there but thats what editing later is for.

Subaru model list and engine configuration, U.S. specifications (As best as I can remember)

LEGACY & OUTBACK

• From 1990 to 1994 Subaru Legacy 2.2L engine, available in L, LS, LSI trim, hydraulic lifters, non interference, the LS and LSI were available with pneumatic suspension to address early ground clearance issues in the Legacy
• Turbo model or “Sport” 2.2l turbo from 1991 to 1994 (non intercooled turbo)
• Turbo discontinued in 1994 in the U.S.
• 1995 brought a redesigned body with a lower stance and the added trim level of “Outback” but the same stance as the Legacy.The 2.2l stayed mostly the same but some configurations were produced with single exhaust port cylinder heads that can be problematic, And we of course started OBD II
• Trim levels were Brighton, L, LS, LSI, Outback
• The 2.5L (DOHC) was introduced in the LS and LSI models in 1995 as an option
• 1996 brought the Legacy GT with a 2.5l engine, Legacy Outback with a 2.2l manual and a 2.5L auto transmission. The Outback has a higher stance but is still just a “trim” level of the Legacy
• The 1996 2.5l has hydraulic valve train and composite head gaskets that are like in design as the 2.2l from 1990 to 1998
• 1997 brings about mechanical valve train in the 2.2 and 2.5l and MLS (Multi Layer Shim) head gaskets in the 2.5l, these gasket tend to have some internal failures resulting in overheating, this can happen as early as 60k but on average most reach over 100k before there are any problems
• Mid year 1998 brings about a redesigned 2.2l in the Legacy which is the design the 2.5l will follow
• 2000 brings about the 2.5L (SOHC) and major overhaul of the models. While the Legacy and Outback are still the same platform they are now separate Models. This is the engine that has the famed external head gasket leak that lead to the WWP-99 campaign. While the coolant leaks were greatly slowed the gaskets can still be problematic for oil leaks and some external coolant and internal leaks as well
• Legacy 2.2l, Legacy GT 2.5l, Outback 2.5L
• 2001 adds the 3.0l H6 in the Outback models only and the VDC(vehicle dynamics control) is standard with the H6, this is a chain driven motor that if well maintained is one of Subau’s best, but if neglected will cost a lot to repair
• The 2.2l is dropped out of production in 2002, and the LL Bean comes out and is only available with the H6
• 2005 is a redesign, and the Legacy GT, and Outback XT is equipped with a intercooled 2.5l Turbo(DOHC) and available 5spd sport shift transmission.  In 2006 we get a Legacy GT Spec B with a 6 speed transmission but is very limited in production

• From 2005 to 2009 there are many refinements and new emissions control devices including the PZEV (Partial Zero Emissions Vehicle) but no major changes
• 2010 is a complete redesign of the Legacy and Outback both becoming larger in size and adding the CVT (Constantly Variable Transmission)

BAHA

Limited production vehicle based on the Outback, was equipped with either a 2.5l or 2.5l Turbo

Forester

• Limited production in 1997 2.5l DOHC
• 1998 Available only with a 2.5l DOHC
• Trim levels 1997 to 2002 L, S
• 1999 2.5l SOHC
• 2003 was a partial redesign and added the X, XS Trim levels
• 2004 on Available with a 2.5L DOHC Turbo in the XT
• Forester LL Bean has an H4
• Some partial changes from 2004 to 2008 but major re-vamp in 2009 making the vehicle larger in size and a much broader appeal
• The 1999 to present all use the same type of head gaskets that the Legacy and Outback

IMPREZA

• Introduced in 1993

Available with a 1.8l and 2.2l until the 1.8l was dropped

• The Impreza RS in 1998 had the 2.5L DOHC in 1998 and the 2.5L SOHC from 1999 to present
• Available starting in 1996 in Outback and Outback sport trim levels
• Trim levels Brighton, L, RS, Outback and Outback Sport, engine configurations varied by trim level
• In 2002 the Impreza WRX made its north American Debut with a 2.0l DOHC Turbo, Followed by the WRX STI in 2004 with a DOHC 2.5l but different from the 2.5 L in the Forester XT, In 2006 the 2.0L was dropped from production in favor of the 2.5L found in the Legacy GT, Outback XT and Forester XT
• The 2007 STI is one of the more popular models as it has a better gear set for around town driving.
• Subaru drops the sedan from the line up favoring a 5-door, only to bring it back as the WRX GT
• The 2011 STI will be available as a sedan

TRIBECA

Came out in 2006 and was redesigned in 2008 only available with the H6, The H6 has changed in size and power but is still the same platform.  This vehicle is packed with features, and has the capability of 7 passenger seating.

The Rest

• Loyale produced from 1985 to 1994 1.8l and 1.8l Turbo, variations of the platform are RX, RS, DL, GL, GL10. The Loyale was virtually unchanged from 1990 to 1994 and was really only kept around as long as it was in the early 90’s because of concerns with the low ground clearance on the Legacy models. There are many configurations of these cars, some with dual range 4wd, turbo and a differential lock
• Justy, we don’t see many of these and no one will pay us to work on them
• SVX, Dropped out of Production 1996 and some 1996 sold as 1997, only available with the 3.3l H6, this was a car well ahead of its time with a lot of unique features. Was available in either 2 or AWD with an automatic Transmission only
• Subaru XT, XT Turbo, XT6 very rare anymore. The XT6 model could be found with electronic power steering, pneumatic suspension and really was a car ahead of its time

Important Notes and tips, (with a bit of sarcasm)

• Clutches are hydraulic starting in 1997 in all 2.5l versions, cable operated in the 1.8l and 2.2l up until 2000 or so. All cable operated clutches require an adjustment from time to time. Most cable operated clutches had a hill holder, a device that makes having a manual transmission on a hill a breeze.
• The 2003 Forester brought back the hill holder but it is a hydraulic and cable operated device.
• Starting in 1999 with the SOHC 2.5l Subaru went to a dual mass type flywheel. Some of these can cause a chattering issue with the clutch.
• For any 1999 and Later SOHC models it is suggested by Subaru to add their coolant conditioner at every instance the coolant is changed.
• There is a parking light rocker switch on the steering column of every Subaru, if bumped will cause the lights to stay on.
• If your battery goes dead, or is replaced and now your lights are flashing, you have tripped your keyless entry/security system even if you didn’t know you had one. If you have a remote press the button, if not or the battery is dead try the following. There is a toggle switch taped to the keyless entry module wiring harness under the dash to the left of the steering column or if you are lucky the installing technician may have done it right and actually installed the toggle switch in the lower dash panel as is should be. Press the switch with the key on and all will be well. The good news is now that you know you have keyless entry you can purchase a remote, program it in and wahoo a new feature.
• 2000 and newer models when the security system is tripped you must turn the the key in the ignition 3 times and the annoying horn noise will stop.
• If you have a seat belt chime driving you crazy try inserting the seat belt into the buckle for, are you ready, 20 TIMES and the noise shall stop, it may take you several tries at this.
• You need to service the battery on your Subaru every year or sooner, with no exceptions.
• It really is a good idea to turn off the head lights and wipers before shutting the car off, that way they wont turn on while trying to start the Subaru in the dead of winter while the wipers are frozen to the windshield, and the battery must deal with the cold, the head lights, the wipers and the starter. Not to mention the radio, heater, seats, you get the picture. The reason your wipers are now running past the windshield is the linkage was damaged when the wiper blades were frozen against the windshield and the wiper motor tried moving them, kind of like a tongue on a frozen flag pole.
• If you want the AWD system to last you want all 4 tires to be of like tread design and depth, so yes if you have a blow out requiring a tire needs to be replaced then yes you should make sure the replacement tire matches what is already on the car. This can be done 2 ways either buy 4 tires or one tire that matches the rest and have it shaved to match. Yes this can be done, but not in a hurry typically and you should never use your space saver tire for much longer than a few miles at low speeds or you will damage the differential. This is why I never suggest you pay a premium for 100,000 mile tires on your Subaru.

• You probably dont need a flush, in fact most likely you dont, if you simply follow the maintenance guide in the owners manual you shouldn’t really need to ever flush your cooling system, or transmission fluid, how ever if you neglect your brake fluid, that may require a flush to remove moisture. You certainly dont need one at every oil change interval, regard less of what the teenager at the lube center tries to tell you.
• The “I” in the maintenance booklet does not mean “Inspect” Look closer at the bottom, in fine print it states “I” = Inspect, Replace or Correct As needed. Do not be fooled into thinking the differential and transmission fluid is good for life. The GL5 gear lube is pretty much the same stuff that has been around, well since before I can remember.
• Your Subaru Doesn’t need brake calipers replaced under normal situations, but it would prefer someone older than 18 replaced the brakes in a car you tote you family around in.
• If you dont tighten the “gas cap” it will cause the check engine light to come on. If you forget to change and check the engine oil and it runs out, the engine may start making some very loud noises before ceasing to function and the “check engine light” will never come on. If your Check engine light flashes you need to stop driving the car. There is one check engine light and many different causes of the light to come on mostly dealing with emissions control devices, but sometimes more severe.
• The ATF Temp light is kind of like the check engine light, and serious if it starts flashing and should be looked at fairly quickly.
• Many newer vehicle will have a flashing cruise control light and no cruise control function if you are ignoring a check engine light(someone is trying to get your attention).
• There truly are no instances when a check engine light will come on for maintenance. The guy that set his crack pipe down long enough to tell you this should be tarred, feathered and then forced to read the entire owners manual plus the service manual just for fun.
• Because the check engine light came on last year for a loose gas cap doesn’t mean its on for a loose gas cap this time, if it is gas cap related, after tightening the gas cap the light should turn off after a few trips in the car, if it doesn’t its not the gas cap this time, its something new that really should at a minimum be looked at and from there decide if its something “worth” repairing.
• Your Subaru, as will every other car cost you a lot more to own than any ownership study will represent.
• If you decide that changing your oil less often than 3 times a year is a good idea, because Subaru and every other Vehicle manufacture makes it confusing, or Synthetics last longer, I assure you if the engine has a major mechanical issue out of warranty Subaru probably wont participate. The Subaru branded filter for all 4 cylinder model Subaru‘s are tiny little.
• If every car lasted 300,000 miles with no real repairs needed how would any car company make a profit?
• A Subaru is a great AWD vehicle with a low center of gravity that will get you to where you are going and take care of you if you are ever in an accident. Through the years Subaru has appealed to many more owners than just the Skier and Hiker with the many different models and trim levels.