There's an air restrictor in the outlet (Where hose to throttle body connects)of the air intake box that you can take out..gets abit noisier, but it's atleast a little more air, very little performance gain but maybe a little, and it's free. just need a flat head screw drivers and some pliers to pull it out. I put a catback on it...get a better catback than the dynomax, I just got mine cuz the exhaust fell apart and it was cheap, still gave a little extra performance and a nice sound, and I've heard when you combine new headers/manifold pipe with a cat back there's a fairly "significant" increase, but that's about all I know. Cold air intake might help a little, snorkel does the same thing but more effectively because it's in a higher air pressure area, And that's just about it. Unless you stick a turbo on it. some company or another makes a turbo kit for it.