Demon paintball were originaly going to be importing the carmatechs, but stopped due to issues. I either recall that it was due to customs issues getting reassurance on the vcra / or that's what my thoughts were.
Magfedpbuk do list the carmatech
The issue with the vcra for an importer/seller is that they could lose their money if it's confiscated at customs, but also could get a major fine and imprisonment.
The onus is on the seller to establish the buyers legitimacy.
There are paintball guns being sold in the uk that could be construed to be RIFs, perhaps the increase in magfed/milsim legitimises their use. We'll only know if someone goes to court
I've no experience of the carmatech, so can't comment on specifics. But it's pretty niche and you can't crank up the velocity for more 'sniper range'