The CS might, as you say, have a different flywheel than the cupcars.
Here is qoute from a british site:
The Clubsport version comes with a bolt-in roll cage, fire extinguisher, bucket seats and single mass flywheel (notice the noise when depressing the clutch whilst stationary).
Emergency cut-off switches, one under the bonnet and one in front of the gear lever. These are for track use only and the external red pull loop is normally stored under the luggage compartment lid.
Found here: http://www.titanic.co.uk/GT3/GT32e.htm
Edit: More info in this buying guide: http://www.parr-uk.co