Is anyone producing rear wishbones to fit the MX rear IRS to a Champion chassis,I just fancy going from live rear end to IRS especially as I have a whole MX as a donor?

I think you would need some sort of rear cage/box structure to mount the wishbones to, if your going for a home brew of mix and match parts start at the uprights buy a cheap set of wishbones then build the suspension cage to suit. If you try and do it the other way round you'll end up having to buy/make custom wishbones. There's also the small matter of how to mount the mx5 diff.

The revised rear structure is taken care of....I intend using the top wishbones that cane with the subframe,and I ' just ! ' need bottom wishbones.