Alot of people goes crazy over Centerforce, another excellent choice and if I wanted to spend more than it cost for my King Cobra (which is awesome for my stock mustang) would be Clutchmaster, they are great. And moderately priced $140 for stock grade and $320 for better than a King Cobra up to $600. I don't have experience with these, but my local race shop MPE Racing in Taunton, MA swears by them. Gripping power per model ranges form stock to 400% over stock!
www.clutchmasters.com