Ahhhh the all mighty header debate....
Run a search on headers and I'm sure you'll find tons of stuff.
Pacesetter headers are good as far as HP gains. However the quality or craftmanship and quality of material is what drives people away (including myself). First of all the craftmanship. Pacesetter headers are known to break or crack at the joints due to improper welding and assembly. And, as everyone else knows, they rust rust rust.....
So if you're looking to replace you rheaders every couple of years, I would definitely go for Pacesetters.
Me, i'm going for Hotshot Ceramic Coated headers when they get built in April. Already have some money down on a set because they go as fast as a chicken in Ethiopia.