A cold air intake that breathes from the fender is the way to go. The GanzFlow ( www.imprezars.com ) and the Cobb ( www.cobbtuning.com ) CAI's are the two best. The Cobb has the highest gains, but the GanzFlow is at almost the same level, but the Cobb is about twice as much. But you can't go wrong with either one, really. I have a GanzFlow, and I love it. As for filters, either a K&N or an Amsoil would be good for the Ganz, but if you get the Cobb, it comes with a PDM inline filter.
I got my ganzflow intake from imprezars.com. It only cost $99 and if you don't have a filter and need to get one it's on $50 more and the best thing about it....no shipping. Adds great sound to the motor.
If you'd like, feel free to take a look at our intake that comes with a filter for 120.00 and that includes shipping.
Find it at our site under specials. Specials
And if you wanted cold air, you could get the Carbon fiber cold air box as well, and still 50 bucks cheaper,
Just a suggestion
Their exhaust is good but I hear their intake isn’t all it’s cracked up to be. I think I’ve read about 30 posts where people have complained it robs their low-end torque away. The guy who gave me a Ganzflow asked for it back after he installed his Cobb. So no, I don’t think it’s worth it; I'd stick with the PDM of Ganz for now. If you don’t live is some busted ass place where they salt the roads in winter just go down to a muffler shop and have them bend you up some 2-1/4” C.A.T. back system out of galvanized with a Flowmaster for like ¼ of the money, installed. But if you’re worried about the stainless look this may not be for you.