Coincedental that you mention suspension tuning Jmac. Recently I've been told my open diff has been spinning both wheels upon a hard launch and side-stepping it, and at the last motorkhana I ran it felt much easier to hold a slide with a heavy tyre in the boot keeping some preload on my rear swaybar and suspension. I really need to drop the back an inch or two and change the hilux shocks for something adjustable down the track.
That poor little diff is like a chamios, getting better with use until it's worn out lol