There are a million and one things u can do to change the performance of the Golf mate, and once u start tweeking you probably won't stop for a long time so get ready to be continually looking for your next mod...having said that its all fun so lets go !!!
Depending on your tastes air filters can change the sound of your car quite a bit, so be wary of cheaper versions and stick to big brand names such as K&N. I can't tell from your pic if your exhaust system is standard or not but this is one thing u can change in preparation for your re-map further down the line. The exhaust won't make a noticeable power difference now but a brand like Milltek will make your car sound sweet and will give u more significant power gains after the re-map.