I love the Ram air idea and always have growing up with a dad that loved Pontiac muscle cars and had quite a few GTO's and Firebirds,  but on our quads it wouldn't be utilized.  I will compare it to a zx12r kawasaki ninja which uses a big ram air induction system it gains 10hp at 150mph and the numbers go down from as the slower you go the pressure drops.  These gains are with a 1200cc fuel injected machine so im sure the results would be less with a 500cc with our current carb setup.  Great idea for looks if done right, but for performance I dont think its the best option.