It seems that 3.07 gears are now available for the M86. I was considering putting 3.23 gears in the rear (that was the next closest ratio till now) to take a bit of load off the box but since turbos like a bit of load, 3.07 will still keep load on the turbo whilst taking a bit of load off the box (does that make sense). Also was looking at the Diff Options. I really prefer a mechanical diff but the two pinion factory diff, even modified will never be able to cop abuse just by the nature of the two pinion design. If it was 4 pinion with seperate halves I would use it. Truetrac/wavetrac, any worm type diff, I see as being a diff centre you put in a girls car. So it really just leaves a KAAZ. In the description of this ebay seller it seems that he refers to some Cone Springs in their centres that make it quieter. http://www.ebay.com.au/itm/KAAZ-LSD-REAR-Ford-Falcon-XR6-Turbo-DAG3830-/151262549009 Also have read that there are some differences in the BF and FG diffs where the FG may need a spacer to fit the DAG 3830 but the BF does not. So it might be better starting off with a stock BF diff for the build. Nevertheless things to look into further.