The 951 fuchs 8" wheel fits well within a standard non-turbo front fender.
I believe the 930 turbo front fender is 2" wider than the 911 front fender.
On the chart below compare the 7x16 and 8x16 911 wheels to see the added 1" or 25mm towards the fender lip. If you were to remove the stock 19mm spacer found on the early floating rotor 930s, then the outboard lip of the 8" wheel would only extend 6mm (1/4") farther than the stock 7x16 wheel, which you would hardly notice.
I believe credit for this chart goes to Bill Verburg though I'm not certain.
