computer is your next point of call. get the emanage or save a little longer and get a power fc or microtech lts12. without a computer to back up your other mods it would be pointless getting a new turbo. also you would need a manifld for the turbo coz of the different flange to the stock 1. means more $$$
IMHO save a little more, get a microtech (epa approved as it is tuner lockable) and set your car up properly first time. once you got your comp, you can stretch the stock injectors to 85% duty cycle, and stock turbo to 10psi everyday driving and you'll c a big difference. or better yet, for like 900 do a trade with slide for your stock turbo and get one of his hi flow turbos after you get the comp.
fmic, 13psi on slide hi flow, hks intake, 3" turbo back zorst, microtech lts12, 85% duty cycle on stock injectors and you should see around 210-220rwKw.
next step, bigger injectors, cams = 230-240rwKw.
its up to you.