the 28 spline units actually do take a lot of abuse. I've seen lots of guys running 10's all day long with no problems, it all depends how you launch it. If you have busted it up, it might be just as easy to get 31 spline units. You naturally will need to change the diff. I know a few guys running 9's using the explorer traction loc unit, and they love it! It's obviously streetable (its a traction loc), and you can get the unit from any of your local ford dealers.....cheap.