2002 Chevy Impala Brakes and Suspenstion Question......

I need to get a Good set of brakes for my car because i have 20" Rims and i really can't stop all that great =( *TEAR* thus i am on here asking this stupid question.. Another problem that i have is i need to get some type of suspention work done to actually lift up the back end of my car because i am also into Sterio Comp's and i have around 400+ pounds just in my trunk so it tends to sag alittle bit . But i put Spring Blocks " dont know exactly what there called " and it lifted the back end alittle bit but if i go over a pump the back tires will rub within the inner wheel well so pretty much i need to know what i could do to actually make my car level and make the ride quality that much better...

Thank you for any help that you could give me ...

I heard, i think something about Camaro brakes on the front ? Not sure though. Have you tried the " W body store "
http://www.wbodystore.com/grandprix/

My son has 2001 Impala with the police package. That model has heavy duty rims, brakes, springs, suspension, radiator etc. I don't know if they're interchangeable with the standard model but I imagine they would be.

Why don't ask your local dealer if you can put the heavy duty parts into your car? You can always get used parts at a lcoal salvage yard for less money if they're interchangeable.