im running an IGT air filter, drop in stock type, flows better than the K&N cones and doesnt have MAF issues.
go for the EAT chip
a good "performace mod" for your engine would be new high power ignition coils and iridium plugs, and a Dinan high flow throttle body, and when replacing those do the valve cover gaskets and intake manifold gaskets.
then change your motor oil to something with lots of Moly in it, like Redline 5W30.
Alusil, Dinan DME | ITG Air Filter | Eibach/Bilstein HD | 26/20 Swaybars | Iridium plugs | Depo/ProLumen HID | Optima batt. | no AC | Stoptech brake lines, Frozen rotors, brass bushings, Superblue