l wanna buy one and trick it out and get the most hp out of it...

05' they seem to be leading as far as power production before they changed the front end

If l bought any ST l Subaru from 2004 onward, l would have a good speedy car that can be modified if you want more out of it. For 2007, Subaru said they were just measuring the HP differently, but that it was still the same.

If u r talking U.S. models, the '06 & later have the 2.5 liter engine as opposed to the 2.0 liter motor from '04-'05. The HP rating is almost the same, but it has more torque down low & is a better *street* motor.

In '07 they removed the sodium-filled valves & went back to the regular ones, so I'd say the '06 probably has the most potential for a street car, assuming you're going to keep the stock short block & heads, as most of the 'tuner' cars u see on the street.

Frankly though, for a strictly street/tuner car, they all pretty much have awesome potential. l think it all depends on ur budget. To get a decent used '04, you're looking at ~$23k & up (in my neck of the woods) & for a nice used '06, you're looking at right around $28-$29k (or more!)

Personally, l prefer the '06-'07 because the torquier motors make it better for typical everyday street driving. (And, l think they look better, too.)

well every model of the sti is awesome! but the 2006+ models have a 2.5 L. more torque, but basically the same hp.

l like the 2004.

anything but the '03 with the 'bug eyes' l like the '05 & on models when it comes to appearance. However when it comes to cracking open the engine.. it will be a btch to take it out & get it to run right afterwards. u will have to drop the engine out of the car to trick it out. however the Sti already has about 300 hp. u really do not need to do anything as that is more than enough on the street unless you're making it into a track car. the easiest thing is to give it a more efficient front mount intercooler & it will bump the power up a bit. maybe a different turbo as well.

Honestly it depends on ur opinion of the styling. Wether it be the 2004s or 2005s, or the 06/07s. The internals r almost exactly the same. The first US-spec ones did NOT have a radio or factory floor mats. Keep that in mind if ur an audiophile.

They've all had the 2.5L closed-deck engine. They've all had the DCCD (driver controllable center differential) unit that lets u adjust the torque application bias between the front & rear axles. Thats a handy little feature for spirited driving in all weather conditions.

The interiors r almost exactly the same in all the years, apart from the radio difference, & the suspension/drivetrains r the same in all years.

One small thing im unsure of is the adjustable headlights. l know the 06s had a feature that would level the headlights as the front end picked up under hard acceleration. That was also driver adjustable.

The comment above about them switching to the 2.5L in 2006 is misguided. That is in reference to the WRX, not the STi model.

Okay, if u r talking about the US models then l have no idea what some people answering r saying.

The USDM STi always came with a 2.5 liter. The WRX, not the STi, that changed its block to the same one as the STi one in 2006. l believe it is the EJ257 block.

Now that we have our cars straight.

It depends on what ur definition of ''tricking out'' is. If u r going to stick ricetastic bodykits & neon lights on it, then dont even bother with the STi. You would be better getting the RS or 2.5i as it is now called & save ur money for parts.

If u r into performance, then the STi is great. The 2007 STi will be the best option due to the yaw controll & the VF43 turbo as opposed to the VF39 used before 2007. Also there r some slight variations in the transmission as far as gear widths r concerned.

Keep in mid that Power & Performance r different things. If u want to drag race then this is not ur car. Although u can get power out of the STi it is not worth it. It is much earier & cheaper to get more power out of a Lancer Evolution.

There r plenty of fast Evos but STis r more limited.

Think about what u want this car for before u decide if u really want this car. It is difficult to get an STi into the 10s or less but it can be done with Evos.

Also due to the block change most poeple now pick up the WRX TR & use the difference in price to make it faster. With Engine management, turbo back exhaust, & a different turbo the TR & WRXs of the 06/07 years can compete very well agains the STi.

Also keep in mind that insurance will be murder in the US for these cars. It is cheaper for me to insure my Porsche than it was to insure my WRX.

For a great place for information l would recommend u check out the latgest Subaru community online at nasioc.com

04 & 05 r the best.

that being said: if u just want a high HP car, dont buy a subaru. Buy an LS1 powered F-body (trans am, firebird formula, or camaro SS), or an LS2 powered pontiac GTO for much cheaper than an STi. mods r also far cheaper because its a much more common engine.

the STi is a car bred for the track (not dragstrip). its not designed as a drag car, so why use it as one? The unrefined american cars do it for much cheaper.

If youre going to use the car on the track, then u dont need to mod it. They come more than fast enough for anyone under club-racer level, & more power would just make it almost undrivable on the track with all the turbo lag & power surges.

l own an 05 sti & love it, but l do also know that it is not a drag car. its not meant to be. Youll crap out so many trannies & blow so many headgaskets & waste so much money it wont even be funny trying to do what u want it to (which it isnt designed for).

ALL usdm ST l is are 2.5 liters

02-05 WRX is are 2.0L
06-07 WRX are 2.5L

theres a diff between a WRX and a WRX STI.