I haven't been back to my local rollers yet to get some graphs so I won't talk in numbers.
In short, its very good. Its not blindingly quicker than a standard clio so its quite easy to forget the difference. But when I drove a friends 172 of similar performance to mine prior to RS2, it felt worlds apart.
The low down torwue just wooshes you along at low speeds, then pulls much harder through the mid range and onto the 7500rpm limit. I'm not sure if it 'throws' itself onto the limit like it used to, but that could just be getting used to it.
Key points to consider
-its not ITBS
-its not about the peak figures, if you haven't driven one, you probably won;t understand
-its VERY drivable. It has the same manors as a standard car
-it sounds awesome
-mpg is not affected, I got 44.5mpg on the way to CSS
-I don't think I could go back.
All in all I'm pretty happy with it.
The cost, considering I would have bought new mounts and a remap at some stage anyway, I consider it to be good value for me. Would it be such great value at full price? (non group buy)... I can't say.