The GMPP kit is seen here
http://www.gmpartsdirect.com/results...ber=pk12456148
As stated, it contains larger front and rear swaybars, a front strut tower brace, and rear tubular trailing arms. I would also recommend either MOOG or Energy Suspension front swaybar endlinks instead of the rubber ones, the rear endlinks are pretty sad too, but the front ones have a more noticeable impact.
http://www.gmpartsdirect.com/results...umber=12498644
That is the retail version of what I have, but I went about it in a much cheaper fashion.
Most 2000 or newer Impalas and Monte Carlos have 12 inch rotors stock. If you can find one with 12 inch rotors, snag the caliper brackets, get yourself some lifetime warranty rotors, and youre good to go.
http://clubgp.com/cgi-asp/mods.asp?modid=3
theres another article that explains what is being done. If your salvage yard will let you, take a tape measure and see what size the rotors are on the Impalas in the yard. Monte Carlos are also an option. As are certain cadillacs. I did a post long ago called "want better brakes?" that has more info in it, and im almost certain most of it is true, even though GM says that Monte Carlo and Impala "may" have that package installed. Dont pay the 300 or more bucks for the kit, its worth it, but not THAT worth it. It is worth the 100 bucks or so you might have in the project by the time you buy a set of rotors.
The only way you could find the handling package used would to be buy it from someone who is demodding, or to find a police issue Impala with the 9C1 handling package.