I've successfully managed to get 1 KMX in a Renault Scenic (a baby Minivan for the US amongst us). All I have to do is take out the middle rear seat completely and fold the backs of the other two down. The trike then reverses into the Scenic and the rear wheel just sits nicely between the seatbacks of the front seats, without getting in the way of handbrake or gear lever. I don't even have to shorten the boom and I'm 1m76 with fairly long legs. Getting it in I have to lift it up, but for gettig it out you just pull it and it rolls out and drops to the ground.
BUT that's one trike alone. I don't think there's the width for two, I suppose if you removed the rear wheel you could probably get two in though by sitting them on their sides. The thing to remember is they're not actually as big as they seem.
PS, what is that folding bike on your site? I'm looking for a couple which will fold small (to get in a FIAT Panda) can youlet me know a bit more?