Mr Z--- I have an '02 C4S with a B & B exhaust (just muffs, w/o the cat by-pass or headers) and the K & N cold air install in place. Its my daily driver, and doesnt see the track, but I now want to go with a chip upgrade. My local tuner ( in whom I have much confidence) likes GIAC chips... did you evaluate GIAC? What led you to your chip selection, and what did it produce?