Even if its just an outlet for hot air, it could lower under bonnet temperatures by over 10°C. Its ideally placed, at the point where the overbonnet airflow sucks hardest (a few inches infront of the windsheild), and its big enough to cover most of the central part of the bonnet.... Rather than directly increasing power, it would alow the engine to make more power in a slightly more idealistic fassion, with the hot air being sucked out more efficiently, giving the cooling system maybe the slightest, oh so slightest, of helping hands.... <{POST_SNAPBACK}> Sorry. On a normal XR8 bonnet there is no wind sucking going on at the back of the bulge. At 120klm's on the freeway, pouring rain, you can watch all the little drops of water dancing around, going no where, on the back of the bulge With the vents it might give it some "flow thru" ventilation, but not much sucking