I just put a set of the cheaper ones on. I think there all the same just sold from different vendors. You will have to re-use your old manifold gaskets or get a set of aftermarket ones, the set they send with the headers are junk!!!! The quality is pretty impressive for the money. The collectors are only 2 1/2", but they seem to get the job done. I don't like the "doughnut" gaskets for the collector connection, but other than that there fine. I'm waiting to see how well they hold up in the winter.
2004 GMC Seirra 1500: 3" Body lift, 295/75 Nitto Terra Grapler's on Stone Crushers, cam keys, Bilstein 5100, 5.3 liter, K&N 77, Stainless longtubes, Banks Monster Exhaust, Nelson Performance 93 tune, 2600 stall, Ls1 fans, Taylor wires, NGK tr55's, TransGo shift kit, Corvette servo, TCI pan, 4.10 G80 w/ TA Performance, Optima