If you are planning to turbo your stock motor first of all you'll have to decide between FMIC or TMIC. I would say buy a Baja turbo hood for you car... top mount will be wayy easier. So from there I would look on rs25.com for people selling 2.5L turbo kits (I always see em on there) Once you get your hands on the hood and turbo kit, then you can pick up some Borla headers and get a 3'' exhaust all the way back. Lastly I wouldn't run any more than 6lbs boost if you want your engine to at least stay alive for a while...but could always upgrade internals thats a whole other thing. Techworks Engineering has some top of the line stuff, check em out. I know someone who's running the FAT (Forced air technologies) turbo kit on his 02 RS so far for 40k miles w/ no problems. Ideally if you can get you hands on a Vishnu kit or Ludespeed that would be the way to go.

 

There are in fact a lot of parts available for your car. Thankfulyl we share the same engine as the 2.5 RS. As for a turbo kit you should decide what kind of power you want and how much you want to spend. There are a number of used kits out there that have not been used for long. That is a much better deal than buying new. As for headers, forget Borla, they are crap. The welding is **** poor and they offer little performance gain. COBB, or TWE headers offer far more power but also cost a fair buck more. As for piping, 3 inch is not neccesarily the way to go. Figure out how much power you think you will be pushing. 2.5 may be ample for what you want. In all honesty though, fo rthe amount you will be spending you would be better off trading your car in for one of the new legacy turbos.

 

Front Mount InterCooler
Top Mount InterCooler

Don't bother with Borla, seriously. But website is borla.com

-cobbtuning.com

also check out: techworkseng.com

It would be cool to see your car "blow away" the 2005, but any slightly modified '05Gt will easily handle your car. But, your choice...I think it would be a cool project.