Hi
I have Aero fenders/wings/mudguards/guards. I think they are 2 inches wider than stock.
On a 1303 with front discs I have 18x8 ET 15 wheels, these have a pretty good fit, I have easily run a 17x8 with ET10.5 with these fenders before.
On the rear I'm running early alloy 944 arms and 18x8 ET 40 wheels, these are close.
Steve
