i can confirm that the rea does, indeedy, do what mike has sugegsted, as anyone whowas watching at ford fair 2 years back will know (pictures of me going backwards round one of the corners, twice, have been circulated ) and that was with standard, albeit new, suspension and the escos rear arb
the back end was certainly twitchy, and even with a megre 130 brake and 125 lb/ft turning 215/45/17's it was enough to unsettle the rear end quite noticably, even on normal roads going round normal bends etc