Originally Posted by THE EVIL TW1N
Don't forget the hp difference, it's pretty big. That alone is ~2.5 mph. And then the weight (50lbs) is another ~.5 mph. Normally a conventional 4 spd auto would result in another 2-3 mph slower, but the 6 speed auto is geared pretty aggressively so it get's some of the mph back.
I'll go with this answer as well ...