I'm well pleased so far with the JCW Kit. Fitted yesterday. Took it out for a wee blast (I had to do 2 runs to get a clear stretch of road...) down the Clyde Valley on the way home last night.
Everything feels 'tighter', and the slight vagueness (if you could call it that) I felt with the previous Sports Suspension - especially when pressing on - seems to have been eradicated. OK, it's stiff over the bumps, but the Sports setup was too, and if anything, the JCW kit seems to 'cushion' away some of the harshness while improving overall control. I had heard some negative reports about the ride quality, but that's cobblers, it's probably about as good as you can get on 17" Runflats, and arguably how it should have come out of the factory. The fact that Factory JCW doesn't get this suspension is a crying shame, it should come as standard on that car, along with the Recaros!
Also, the 'stance' of the car is much better, as it doesn't look as if it's on stilts, and it still clears the speed bumps - so far.
I had a run a year or so ago in my pal's Porsche Cayman S (he now has a Nissan GTR). I was totally impressed with the wee Porsche (it was the best handling car I've been in apart from his new GTR which is just on another planet) and I have to say that my MINI with the JCW/Milltek upgrades and JCW seats etc now feels just about in the Cayman's league (give or take a few BHP!) when pressing on - and slowing down - which is pretty high praise, and a saving of about £23K! Result.