I just got a 2003 gti in very good condition. The problem is I only have about 300-400 to customize it. What could I get to increase the curb appeal in this price range?

hello i have a '03 mkiv 1.8t .... i have apr stage 3 chip , ko4s turbo, custom catback exhaust, stage 2 clutch, and a couple other things.... but i was wondering what else besides front mount intcooler could add more hp? any advice .... also a friend of mine has a stock '03 tiburon gt with a...