I highly recommend AT LEAST Hawk Blues. we have single piston calipers and the Blues worked well for a full day of racing CMP- Southern Discomfort. they felt a bit faded by the end of the day but when we changed them out it seems that the edges of the pad were bent back so we were probably only using 40% of the inside pad surfaces. there was still plenty of material left though and I'm convinced they would have went the whole race if we were running dual-piston calipers.
Now, we had swapped in HP+ pads for day 2, BAAAAD MOVE. complete caliper destruction with disc damage (pistons went through the pads)
this all being said, it's also all VERY dependent on the track you're planning to race. Wagner Severe Duty, Blues, Satisfied Pro makes a fleet pad that's supposed to be better than the wagners, Mid-level Carbotechs are all great. if the track you're running has at least 2 heavy braking zones like CMP, don't cheap out.