need a little help on building my rear

Im a big fan of the truetrac, I worked on a sae race car when i was in college and we used a similar design for our diff. I was blown away how it worked, the gear type is the only way to go in my opinion.
I think an original Torsen diff is the kats pajamas, but the truetrac is very similar in design.
Truetrac
[ame="http://www.youtube.com/watch?v=lZmsY2YvVsc"]YouTube - Exploded View - Inside the Eaton TrueTrac Differential[/ame]
Torsen
[ame="http://www.youtube.com/watch?v=Z9iPqIQ_8iM"]YouTube - Diferencial Torsen (Autoblocante) / Self-locking Torsen Differential[/ame]