An 02 car will be the same as an 03, but only available as a JDM (UK cars were released late 03)
07+ cars have twin intakes so a normal sc won't fit, there is a kit in development for the later cars though.
I fitted my sc at 35K miles & am still on stock clutch & fly. I've only done about 1500miles since fitting it but it hasn't missed a beat.
No essential mods really but if you get a car with plenum spacer, cats, y-pipe & exhaust already fitted you can make more power at a lower boost level which is ideal
Do a search about the stillen one, someone went to look at it recently and pulled out of buying it.
I also think you will be very lucky to get anywhere near those figures with the stillen kit, they are not known for making the best power although they do make the best sound
I would sell mine but not at 15k