I followed your install thread and found that this to be quite amazing. My car, with intake, pullies and exhaust probably touches 200whp - your car has a whopping 30 more whp! Given the price of ZHP cams (600) and ebay headers (100) it would theoretically cost someone ~$700 in parts to add a solid 20whp to their M54B30 - talk about about budget modding!
so have you tried some pulls against anyone yet? e36 M3's make about 220 to the wheels...
I'll make an uneducated guess and say your car can make another 8whp with a proper tune.