red,
Yes, adds down force; ask JonB (Parts Rack), how much down force this Mopar Spoiler adds to the rear of the car at 100mph, 120mph, 140mph, I can't remember. At the track I regularly run 140+ (all the straight will allow for my car) and know the spoiler works. Besides, adds looks (in my opinion) to an otherwise drab RT/10 rear end.
Later,