I've had TTI's and Hedman Huslers. I'll take the Hedman everyday even if I do have to drill a hole in each side fenderwell. I spoke with Ryan Johnson years ago and he said the Hedman made more power than TTI's.
That Hedman is a good piece. Had them on the dyno and they work.
My favorite non W2 header is the Hooker 5303 which is no longer made. They couldn't sell them because A) they are slip together and 2) everyone says they are too big. Neither of which is true.