I had JCW Stage 1 installed on my Clubman S Automatic the week before MINIS on the Dragon.

I have to say, I'm pretty impressed by the kit, much better power through the bands. And it COMPLETELY smoothed out the automatic transmission. I hated the auto in sport mode because of the herky jerky shifting. This really smoothed it out and could not be happier.

I did NOT have them install the JCW Stage 1 exhaust because of the drone and I truly did not like the sound of the JCW exhaust. I put on a Remus Axle Back exhaust and LOVE it. There is a thread in the clubman area and can be found here.

What I like about the JCW S1
additional power
Smoother automatic transmission
MINI Warranty
Better sound from intake
NO oil filter to clog MAS air sensor
Better sound of Remus exhaust
Engine is quieter!
I'm getting better gas mileage...don't know how, but I am
Eliminated torque steer, new Programming must have added update
OTHER tunes...ALTA, cannot get auto trans working properly

If you have an auto and are contemplating JCW S1, I highly recommend it!

 

to be precise, the JCW Tuning kit, yes?
Also, what do you mean "ALTA cannot get auto trans working properly"

are you comparing this to ALTA tune, or you're saying after the JCW kit you had trouble with the alta tuning?

 

I have heard and seen too many issues with the Alta tune and the auto trans. That is why I didn't go with the Alta tune and stays with the JCW.

 

+1! I was gobsmacked at the improvement in the auto mapping.

 

Having installed now through an amazing deal...

Where did they put the JCW logo on the barn doors? They asked me, I said under "CooperS"...