You've already modded your car ... and don't know what engine is in it ...

lol
Since its the Golf, not GTI, I assume its just the 2.0L .. if it's a TDI, have fun lol
an ECU chip, exhaust, and intake prolly run ~$1000 or maybe a bit more I'd think
In an unrelated question, I assume most/all mods void parts/all of one's warranty? I just bought a Golf with a 2-year warranty, but don't wanna kill it by modding immediately =\