98 SVT
Hey I recently picked up a 2001 S4 myself. It was stock when I bought it but since than I have installed some mods. While I have not driven other chipped cars, I had a APR Stage II+ installed and am very happy with it. While I agree that APR in normal chipped mode may not have the raw power that the others have it seems like a great compromise between performance and reliability. Also if you aren't happy you can use their race program with 100 octance gas and have substancially more power. In the end you will probably be happy with any of the major chip tuners (APR, MTM, ABT, GIAC).
Andy
