There isn't a lot you can do.You might be able to get a few extra horses out of it but nothing that will make a difference.The best thing you can do is put the money towards the Gti
how is the 1.6 on fuel btw?
haha funny thing is.. I was asking because I also had a 1.6 mk4 auto.. I loved the car to bits! but I was putting 10 pound fuel everyday! lol