Help on Mustangs?

[MsTnG_bXr]

I am about a week away from getting a car. I was looking at a 2005-2006 Mustang GT (Tungsten or Ancient Lime green.) I was wondering if anyone could tell me what some good up grades to get to boost the Horse power and sound. Any help would be greatly appreciated.

 

[Next_Please]

Horsepower-Any CAI+Tune combo
Sound-Any axle-back exhaust

Both around the 500$ range and the best starter mods imo