What brand are you looking at? I put a Bestemusa carbon front fender on my '07 TT 1050 and it is great. Because it drops down about 3 inches longer in the back, I no longer gets clouds of steam coming off the radiator at stop signs when driving in the rain (I live in Vancouver BC... it rains a lot).
HOWEVER... If I remember correctly, the mounting holes were the same size width as the threads of the OEM bolts, but did not take into account that those OEM bolts have a built in spacer / flange. My mechanic looked around the shop and found a set of four flangeless bolts, put some rubber washers on for good measure and I was off! I did write to Bestemusa about it because you take a big risk if you try to drill out the holes on carbon fibre parts I am told, but I did not hear back from them that I recall.
I would be interested in knowing what you decide to do.