What year is your 5.3? All you really need is a good running 05-06 4.8/5.3/6.0 for up to 800 rwhp. No need to buy rods, pistons, crank, etc. The factory gen 4 rods have really proven themselves in high HP boosted applications.
If you are satisfied with 500-550rwhp, then the gen 3 rods...