Porsche 928 wheels on a mk1???

hi everyone happy new year i want to put some porsche 928 wheels on my cabbie the fronts are 7j 16s and the rears 8.5j 16s i think  now how difficult is it to get these wheels to fit they have an offset of 65 and before anyone says they are 5 stud i know i will need spacer adapters to change from 4 to 5 stud but will i need to make any drastic alterations to the arches?

many thanks Sean

p.s. the tyre size is 205/45 R16

Well i have them fitted with 195 40 16 tyres with a 25mm adapters and they fit fine with no rub.. But if you was after fitting the wheel under the arch then they will need to be rolled...