I've been considering a center diff for this upcoming season (we run them on parking lot tracks) but only because I dislike the performance and reliability of the stock 2-speed so much. If the 2-speed worked with high-torque engines I'd stick with it.
I believe that if you run 150K to 300K oil it's really not going to act like a diff at all. Rather it will act like a single-speed.
The biggest question is whether you like your rear a little loose so that you can powerslide the car or whether you want your rear planted.
If your style is to powerslide the car somewhat, a center diff won't help you and the only reason to put one in would be if you dislike the 2-speed and you just want something solid there (with 150K to 300K oil).
If on the other hand you like your rear planted then a center diff could help your cornering somewhat but you'd want to put something more like 30K oil in there. In this case I'd try 50K front, 30K center, and 10K rear.
I can't speak to the torsen diffs. I have some impressions about their purpose but I need to learn more.
Last edited by Arboleda; 02-27-2008 at 09:18 AM.