Just seen the thread so ill add my bit :) , what do u want the car for mate, show car or actually using it, to be honest with out spending alot of money and not being tempeted to up the boost and blow your engine the supercharger is the best option on the is200, also being slightly younger im sure you like doing your own gears (not that scar face is past it LOLOL)
The supercharger can be got up to around 220-230bhp at the fly so 190 - 200 at wheels with a pully upgrade/camcon(fueling)/full exhaust system etc.
If you turbo the is200 you wont get much more with out doing internals which is big money, daza is the first to do internals and is on 300bhp at the fly.
Its all what you can mainly insure at our age and the supercharger is on a few insurence sites drop down menus so it is well recognised
Hope it helps.
Elliott