Id stick with the Cold air its more dense air, which allows more and works better, so ive been told. I wouldnt bother, i personally think Ram Air is B.S. mainly and from what bootsy said, just not worth the money and hassel.
ya i have the ram air air hood with the kit, i dont have problems with leaves or anything like that because there are two screens in the hood. Performance wise i have no idea i bought the car with it already on but i really dont think it is that big of a difference. As for the under bumper my friend has that and he has to clean his filter like once a weak because of leaves and random things
If any power increase, it would only be at top end of the track when the speed is high enough to get a little bit of ram effect. the piping is so convoluted though, I would think it would hurt power at low speeds.