You guys not worried about the resale value of the cars with all the modifications you guys are doing.Sorry for the voice of doom comment but it is one of the things that is holding me back making some performance upgrades.Jim
^^^ Simples, just keep all the stock parts and put it back to standard I did this on my last car, a stage 2+ Edition 30, got over 60% of the parts price back via ebay and forums and a strong price for the standard car.
Go on Jimmy you know you want to
^^^ Just the Turbo Back Exhaust, but most people also fit an intake or at least a panel filter.
Intercooler isnt required but will keep things nice and cool. You probably get away with a 3" downpipe and sports cat???