D90's

Hi all need some advice. I have a set of 16" Porsche D90's on my van with 25mm adaptors but i am now thinking of polishing these and fitting them to my mk1 gti when its finished. The thing is i want the car sitting low so don't really want the adaptors pushing it out any more, so i was thinking of drilling and tapping rear drums and doing similar on the front hubs with porsche discs fitted. Does anyone know if this has been done before, or any problems i might come into? cheers Rich :dontknow: