What I have heard about Pacesetters is, they have fitment issues, and not as good of quality as Kooks or QTP. Also the best you can get in the Pacesetters is coated steel, which will eventually rust. Some have said as little as eight months. Personally, if I am going throught the trouble of installing headers, I want to do it only once, and not have to deal with headers hitting the K-member or the coating flaking. My recomendation is QTP, only because I can find more info, and better pictures of them vs Kooks. You can find some info on Kooks, but it is general. The QTP website has great info on the LS1 headers, plus QTP's have that turbulence spike (in theory it sounds good, not sure how much of an affect it has), My.02