At this point I had a 172 sat next to the Twingo and began dismantling the 172 and trying all the bit on the Twingo to see what would fit.
In the end I decided on using the following off the 172:
Engine
Gearbox
Driveshafts
Exhaust as far as the back of the cat
radiator
Front and rear brakes (std is front 239x8mm, rear drums)
front hubs
gear linkage
From the Twingo I'd use a modified front subframe and rear beam modified to use disks. Wishbones and steering rack.
I wanted to use as many standard parts as possible, but that isn't always so easy.
First major purchase was a set of H+R coilovers
Then did the relatively simple job of drilling and tapping the rear beam to fit the 172 disks. Taking the opportunity to slip in some shim for a bit of ghetto camber..
strangely, although the Twingo is a fair bit shorter than the Clio I had to make an extension for the handbrake linkage.
I also bought a cup brake pressure regulator to fit in the rear brake lines
