customgrandam.com you can try there, they have sum exterior and interior mods for cheap you can also try
grafxwerks.com they as well have sum cheapo mods for makin the car look good, but for performance your gunna be looking into spending sum cash you could get a drop in K&N filter for like 60 bux or something offline but your better off saving a little more to just get a new intake with a Cone Filter, but other then the little look mods like xero said you could paint you interior or calipers and put neons in or around the car, just try to be creative its your car and watever you wanna do to it, do it cuz its your customization so who cares what others think, good luck and Welcome to the Forums
oh yea forgot to give ya this site its a bit pricey but the stuff the guy has is insane
CustomAutoAccents.com