[Jimbocobra]

They use an open differential as standard. There are a lot of good reasons why you might want it on the street for safety reasons, especially for new drivers who might wreck the car getting too agressive on a turn or loose pavement. A limited slip is more predictable on the track, but more prone to spinning. With my open differential car, I can assure you, when hit the throttle or intentionally try to light the tires, both back wheels will spin and leave matching black stripes on the blacktop. As far as gear ratio, depends if you want to drag race it or have an all around car. A 3.46 gear ratio will give you a nice, usable 1st gear. You have enough power that going much higher might just cause you to have to buy new tires more often. Even with that tall of a gear, you can still render 1st and 2nd gear useless by mashin the go-peddle to fast...