well i figured the 4-1 header, that the cat bolts into, would be fine, DC makes one that deletes the cat all togehter, and one that has the cat hook up, theyll just make one that has a detachable cat, so i can still get all the right gains, i was looking at the 4-1 race headers, and it looks like a normal 4-1 but with a flex pipe where the cat would be