Rear gear upgarde????
Talk to these guys
http://www.dynotech-eng.com/dte_c6_diff.htm
Then find a shop compotent enough to swap it with your current diff and return it for the core deposit.
http://www.dynotech-eng.com/dte_c6_diff.htm
Then find a shop compotent enough to swap it with your current diff and return it for the core deposit.







