Everything has its pro's & con's, I would prefer it to be not demountable as it adds weight, height and if a pickup is used then quite a bit of space is wasted on the flip side the vehicle is still a useable pickup when the camper is off, the choice is yours. The Ibex has a 300tdi and when Wal the owner took it for a run over the M62 thought he had made a bad choice as he was down to 3rd I think. He has since put a larger intercooler in and messed with the fueling and is much happier with it. My Dads Rapier now has a chipped TD5 (170HP) and he is very happy with it. Wal built a crewcab as he envisaged taking his grand children with him, AFAIK one of them has been with him once. My Dad has toyed for several years about turning his demountable into a fixed camper as he would drop an estimated 250kg, reduce height and reduce his overhang and be able to accesss the camper directly in inclement weather but for me he might aswell start again. A 150" wheelbase if it were not a Crewcab would be a nice size for a camper, I am fairly sure the Ibex has a 150" WB.
Gaza