At the moment I am about to start the build of a locost 7 (lotus 7 replica) and on the aussie builder's website of late the De-Dion rear axle has been a hot topic. basically from my limited understanding the dd combines the best attributes of a solid axle with the flexibility of an IRS and is able to package the two in a small area for a relatively small outlay. (and is easy to build for people who don't have degrees in automotive engineering and want to build something that has been tried and tested and will work straight out of the box ehe) anyway here is a pic of it. I'm sure with minimal fabrication one of these could be built into a 1200 and you could choose any diff you wanted (say R180 or even 200 if you're really gonna abuse it) and you can get LSDs fairly cheap (like OBX's) or KAAZ (on the more expensive side) and readily available. anyway here is a pic so you can get a basic grip of what I'm trying to say..