Has anyone any thoughts on or experience of driving in france or Germany with a full decat system.Whats the chances of getting tested and whats the consequences? I've heard that the french cops can be pretty ruthless with GB drivers who break any laws so I'm a bit nervous about taking my car there.Dont want it impounded or anything.

If your car is registered in the UK, then it has to comply with UK regulations, which may be different from French ones. I think they cant do much about it ;)