Mine is from US Body Source in Florida. It needed to be blocked and one low spot on the front filled, otherwise fit was great. The underside is finished and it is a bolt on. At $589 plus shipping it was not cheap, it is not light either, about 20 pounds less than a stock hood.
I like that there is no bulky looking bracing under it.
The car has been driven at 130 mph on a closed course and the hood was not ripped off so the bolt on points must be solid.