You can only upgrade the rear sway bar. The front is already upgraded and the mounting is different from the 03's. Best mods for handling on that car is the rear sway bar (same as 03) strut tower braces and the GMPP HD trailing arms. The stock trailing arms are stamped thin metal that you can bend with you hands. The HD trailing arms are solid steel tubes and way better.
Here's the info. I ordered from Paceperformance.com
12498642 - W-car Heavy Duty Rear Stabalizer Bar Package for '97-03 Grand Prix.
Part#: 12498642
Manufacturer Part#: 12498642
(Qty: 1 x $42.95)
12498649 - W-car High Performance "Tubular" Rear Trailing Arm Package for 97-04 Grand Prix.
Part#: 12498649
Manufacturer Part#: 12498649
(Qty: 1 x $43.95)
12498648 - W-car Strut Tower Brace Package for '97-03 Grand Prix.
Part#: 12498648
Manufacturer Part#: 12498648
(Qty: 1 x $22.95)
The strut tower braces requires some brackets if you don't want to drill holes (PM me if you need some). You could also grab the strut tower braces from Wbody store. They are a bit more $ but you don't need to buy the brackets.
Hope that helps....
