Don't know if it would be noticeable on the street, but TTIs are stepped 1 5/8"-1 3/4" while Dougs are a straight 1 5/8".

Fit and durability are second to none. As for coatings, I've had to touch mine up over the years. But I'm more interested in performance and fit rather than finish. Constant tuning and extended periods of non-use in the Florida humidity tends to affect coatings and cause corrosion on everything.