I drove a Dealer modded 18" wheels and tires on a 05' GT mustang it felt like it was pulling maybe 7.5, 0-60. Most of the weight on our rear wheels & tire I think close to 50 lbs each. And not having 50+ hp more is the main reason our cars our slow 0-60 but after we're rolling unless you can't shift that crappy MB 6 speed is going to make you feel like your standing still. That's why I got the autostick just floor it and hold on! The ECU chip also helps.