CAI (personal preference: Injen, not the short one), exhaust...those two will wake up your vehicle as well as change the sound. RX catch can, RX ported throttle body, MACE 25mm intake insulator...fairly easy mod to do yourself. Shorttie headers. If you go long tubes, I suggest getting high flow cats at the same time unless you go cat less. With long tubes, you will need a tune by trifecta to eliminate the CEL. I recommend it anyhow as the tune alone will add HP, firm up your shifts and then tie everything together. The tune alone makes it funner to drive...all in that order or all at once
oh...and something to monitor you engine...like Bluetooth elm device with an iPhone or android app or the aero force gauges...very VERY IMPORTANT!