There has been a bit of a clampdown on modified cars going out on the ring, loads of reasons behind it but until a few groups go over in 2008 I can't comment on how they will police it.
We went in September this year and they had the arse with my mate in his caged Sierra Cosworth, I also know of a few people who have been turned away due to the marshalls not liking soemthing about the cars.
There was a thread on here about it somewhere