Check the performance truck magazines or search online for replacement calipers or complete brake kits. I upgraded the brakes on my 1998 Chevy Tahoe and it made a world of difference. The OEM rotors were too warped at 32,000 miles to be turned and the brakes overall were terrible. The new rotors and calipers never needed work for the next 140,000 miles I put on the SUV.
GM upgraded the brakes on the 1999 models as they knew that what they had engineered was marginal at best.