No performance loss at all,goes like stuff off a shovel,adding new disks, and DS1.11 pads, before Cadwell on 1st September. When on track, I remove engine/filter covers, and also number plate, as it has holes behind it, and of course the bonnet Louvre covers, and as you can see, the rubber strip below the windscreen, and of course, together with the rad fan, now blowing the right way, I don't seem to get any overheating, and very little temperature rise.