Sorry to bump an old thread. Just thought I'd throw in some input.

02-05 WRX has a EJ20 engine, 2.0 liters, Mitsubishi TD04 turbo the 06-07 models use an EJ25 2.5 Liter engine with the same turbo. The 06+ WRX also removes a cat from the upipe which the 02-05 models have.

04-07 STI has the EJ25 2.5 liters, IHI VF39 turbo, larger intercooler, 6-speed tranny with DCCD (driver controled center diff which can change the front to rear bias of the AWD)

Utec is one option for engine managment in a WRX, but most people now use a Cobb accessport which isn't a piggyback, but just a tool to reflash the ECU. Many people buy a downpipe and use the Accessport to flash to Stage II, which completely changes the nature of the WRX, and gives it about 285bhp on 93 octane (claimed by cobb). People with a stage 2 WRX generally run about 13.7 in the 1/4 mile, however some run as low as 13.2, and I've seen the timeslip of a stage 2 WRX at 12.9. You can have a used stage 2 setup for as little as $600. 600 bucks and 50hp isn't too bad. A stage II setup can also be done to an STI with similar results. If a WRX is professionally tuned at stage II, it's not uncommon to see 240whp, and one WRX I know hit over 300wTQ with a tune and stage II.

The VF39 is a direct bolt on for the WRX, but you really need the STI intercooler, and a turboback exhaust with aprofessional tune to run it properly.

The WRX tranny is the weak point of the engine, and really only holds about 300whp before problems arise. As long as the car isn't launched hard or clutch dropped at 5K rpm, the tranny will hold up fine to stage 2 power levels. The STI tranny is nearly bulletproof, and can handle 500whp+. STI interals are the weak point, and owners looking for big power gains often replace them with Japanese STI spec forged rods.

Hope that cleared things up a little.

 

thanks ?

 

^^?

 

haha its like those claritin commercials.

 

I have both an 04 a4 quattro tip and and 03 wrx wagon. 03 stock wrx's typically are in the mid 14's with a full exhaust and intake probally low 14's high 13's depending on driver. I can see a modded 07 a4 beating a slightly modded wrx but not destroying one, unless the guy driving was an idiot or it was an auto because in wrx's the autos are dogs.

 

thats what i like to hear bout dem audis! ahhyeeeee

 

i still dont see how this is. my buddy has a 03 wrx and i ride in it all the time. my 1.8t felt no where near as fast as that thing. note i have never driven in a b7 a4.

 

I have a 05 wrx and a big difference between the wrx and sti is the turbo and intercooler. But good news as of tomorrow, i am getting rid of my damn subie and picking up a beautiful audi a4 2005 b6 body style? i think i dunno much about these cars but plan to learn real fast.

 

gah im sick of this. i will get my friend to race his 03 wrx vs a 1999 a4 with a giac chip

 

An Exhaust itself dosen't add alot of power, and an intake won't add any power. WRX's are similar to Audi's for the fact that engine managment generally adds a significant amount of power, and many people opt just for the EM first, and exhaust later. EM by itself adds about 30bhp, EM and exhaust adds about 50bhp.