From everything that i have seen the only advantage of the ls6 intake on our trucks is it gives you more room. The ls6 intake is good if you are going to be spinning you engine out past 6500 rpm. I dont thing you will be. As far as heads go, I would say for the price that you are going to pay for heads dont. Go forced induction. You mentioned about pulling, if you are planning on pulling much then you need you hp and tq down low. Ls6 heads and intake move your hp and tq up high. However forced induction works great for towing. There are a couple of quys on here running the new sts turbo kit on there 1500hd. They use them for towing.. Look for Jerry2500 and Bud8Fan if you have questions about it. As far as tuning goes, get aholod of Allen at Nelson Performance he will hook you up with what you need. Either way good luck and dont hesitate to post any questions.
04 Sierra Denali
Blown,Cam'd,stall'd etc.