I'm trying to comprehend the use of bushes in the mounting of the diff and rear suspension cradle on IRS models (other than maybe noise or vibration from the diff into the passenger cabin?). The way I see it, the rear suspension already has rubber mounts in the suspension arm pivots as well as the shock absorbers and the spring mounts. Having more rubber mounts for the diff and the rear cradle mounts just allows more flex where it's not needed. Allowing the diff housing to torque up against the cradle mount through the very weak factory rubber mount no doubt contributes to the broken rear cradle problem common to the VR/VS models (what did Holden do to fix this problem on the subsequent VT- VY models?). I know that the best solution is to use the Harrop sports diff mount, however this is probably overkill for the average build and it's very pricy to boot. The cheaper option seems to be a Nolathane insert that fits inside the standard rubber mount to fill the empty voids but this still leaves a lot of rubber which is prone to flexing and degrades badly with age. At this stage I don't see any other commercially available options. Now, I'm wondering. What effect would it have to use solid mounts for the rear cradle/diff? If there is no flex than things won't break (I could do this fairly easily at work). The other option is to manufacture some sort of diff mount using some small solid type Nolathane bushes but otherwise uses the factory diff cover. Thoughts, suggestions or ideas welcome.