Are Doug's headers worth it over my Summit headers?

TTI or Dougs - both are REALLY expensive. However, years ago I had a set of Blackjack headers, which were Cyclones, I believe... Those headers hit the oil pan, the power steering box, and the steering coupler (occasionally locking the steering in the middle of a right hand turn). Plus, they got rusty, they leaked, they hung low and they knocked the grease fitting right off my passenger's side inner tie rod.

I have TTI's now and would buy them again in a second. Dougs are just as good.

I get the impression that you're wondering if there is a performance gain. Probably not.