ATB is an excellent mod. It doesn't increase understeer, unless you spin both wheels, but up to that point you have more grip. So thats a driver issue, not the diff.
The ATB for my 205 was £500, gutted its so expensive for the clio.
Does anyone have one with ESP? How do they work together?
I think the problems with the Focus RS are just picky, you can't have all the performance mods and not expect some compromise. It would put me off. Plus the clios don't have the low down grunt of the turbo charged Focus.