I spend most of the time in my car on the road courses and auto-x so this info is probably not for everyone, but for the guys that do the same it may be helpful.
After repeatedly killing Tru-tracs I started looking for alternative solutions for differentials that would live and be rebuildable, unlike the Tru-trac that you throw in the trash once it starts slipping. I tried using a locker with the lightest spring available but the car would not turn well under throttle, it plowed like a dump truck if you gave it any throttle input in the corners.
I found this billet diff. made by Larsen Racing that can be rebuilt and has the ability to tune the amount of pre-load the helical gears have. So far I'm happy with it's performance and would recommend it to anyone looking for an alternative to a Tru-trac.
http://www.larsenracingproducts.com/...1-4-tight.html