You might contact this seller. His listing has recently ended but looks like he did not sell it . . .

http://www.ebay.com/itm/Chrysler-Crossfire-Rear-Differential-Fits-SRT-3-07-Ratio-Works-Perfectly-/231697442007?vxp=mtr&hash=item35f23e64d7%3Ag%3Aw1kAAOSwsB9WAZiw&nma=true&si=7Nc2oKV8DfPFcWHsZeeYrqVlK3M%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557