One of the fellas on here or the other GTI website has done a fair bit to his and got the BHP upto the 145 mark IIRC. Have you had a chat to TSR?? They do cams, heads etc. I looked into it but its really expensive and cheaper to flog it and buy a 16V, but I inderstand where you're coming from, I reckon it would go pretty well especially if you opened the head up a bit to match. A few years ago a chap called Bill Blydenstein (sp) used to have a lot of success with heads, he'll be found through google no doubt.