Mk III Owners Manual Third Edition - Second Strike

Appendix A: ZF IRS DifferentialFebruary 2010.In late 2009 around approximately car number 2977,Superformance changed the differential in the Mk III and beganusing the ZF IRS (independent rear suspension) limited slipdifferential with a 3.45:1 ratio.The ZF differential is produced by ZF Lemforder in Australia forthe GM Holden line of cars, replacing the differential from BTRAutomotive. The ZF IRS differential can be identified by the ZFlogo cast into the rear of the differential housing.[Figure A1 – Rear of ZF IRS Differential]The mounting points on the Ford 8.8 IRS, BTR IRS, and ZF IRSare not the same. Switching from one to the other requiresmodifications to the Mk III chassis mounting points.Page 199