An LSD also helps with launch. Without LSD, you can spin 1 tire on the launch.
LSD = Limited Slip Differential.
The general limits between the two wheels are 60%/40% allowing one wheel to spin a tad faster when turning corners at low speed without chirping the outside tire. However, when you launch, the 60/40 also plays a roll in making sure BOTH tires receive power. If you're on street tires, you'll find that you pull a peg leg if you don't have LSD. (Or in some mustang cases, WORKING LSD. LOL)
With drag-radials, I blew up my stock LSD on my Trans Am. But on street tire, they should last a while as long as you make sure it's always got oil.