The GMPP kit should work on all 97-03 Regal GS/LS. ZZP offers a similar GMPP kit but you can get just the front stabilizer bar and it comes with the proper sized mid-point bushings. So checkout the link below.
Click here
The kit shown in your link has the strut front crossbar (Strut Tower Brace) but you should already have one installed stock unlike the other GM sister cars. Even a Grand Prix doesn't come stock with the strut cross bar.
Since the stabilizer bar is cracked I'd get that replaced first before doing any further troubleshooting or parts replacement on the front or rear end.