If you're planning on going out in the desert then go with people who've done it before and make sure you have the right equipment for recovery etc - a tow point welded to the underneath of the car is NOT a recovery point!
Best of all - join a club - I'd suggest Dubai 4x4 Dubai 4X4 dot COM Phil is the boss there, he has an FJ40 - anything you want to know, he's your man.
Andy, thanks. I have been out in the dunes many times now, I 'll think I can manage. Regarding your suggestion, it looks to be an older model, for maritime purposes. I was just wondering how the models with touchscreen hold up? Are they any better than, lets say, the Colorado range... Cheers