if you want a cold air intake go with K@N not to expensive, gives a good higher rpm pull. if money is not a problem get a full exhaust system, long tubes, an x pipe with high flow cats, and a nice exhaust system, i have slp power flo exhaust so cant help with your two picks flowmaster and magnaflo. another cheap mod is rear end gears, maybe some 373's. also you can get an engine management system for your 08, $400 its called an X3 made by SCT, i have an live wire tuner, its a little more expensive because has a bigger memory for data logging, but the X3 will bring the same amount of power. this mod should be done after intake and exhaust.