well, for more power depends how far your wallett opens, if not wide enuf, then cat back zorst(2.25), Cold Air Intake if your willing to do it, good service of the car, advanceing of time to 22degrees BUT must runn it on Premium Unleaded Petrol (PULP) to stop pinging
if your wallett is opening more then that then you can get extras like extractors, highflow cat, K&N panel filter(recomended for the CAI), new bigger high tension leads (8mm or 9mm but not sure bout 9's) and if yop got the money then you could get a factory turbo set up for about 2 grand
JUST REMBER IF U WANT TO GO FAST YOU GOT TO STOP FASTER, SO UPGRADE THE BRAKES AND SUSPENSION.....