i tried both short ram and k&n drop in filter.. i would go with K&N.. short ram you lose torque on low rpms (like most people say). also, it sounds cool, but after a while it gets annoying when you have to go uphill and your intake is screaming like crazy..
with K&N, its pretty much similar to stock.. but throttle response in mid range rpm is much improved compared to stock filter. also, when you push the throttle, it sounds nice too, kinda like short ram but toned down a lot.. plus, i dont have to worry about smog checks anymore.. overall, i like K&N a lot better than short ram..
i never tried CAI, but it would work the same as stock setup, so why spend money on it..