i agree with silver gts-t on the order of mods, but i'd put the turbo and suspension before the wheels.
im actually not bothering with wheels at the moment, just some decent tyres. looking at my car now, i regret spending money on things like the paint job and 19" chromies. i could've had my car up at 300kw if i spent the money on performance mods.
wheels are definately the last thing id do though.