Have you spoken to bmw uk motability advisor ?? maybe they could discuss the mods you require and help come up with a suitable solution /mod .I had a x5 3.0d and couldnt fault it another site called
www.x5world.com is fabulous so informative maybe if you go on there and ask what people have done or can be done ? .I had a ml 320 for 3 years and was so dissapointed with loose trim etc etc IMHO it would always be a bmw x5 ,good luck whatever you decide