Hey Issam... I knew the sad news on facebook
it's like loosing a child whenever i know that a friend is selling his X5...
So to keep you in the club, I would recommend the X5
seriousely, it's brand new, no repairs hustle, and once you drive an X5 you can't go to other make...
now about the budget, I think it's the most determining factor, cause we're talking more than 30K difference with the 545!! but again, you'll be changing your whole concept and vision regarding the car you're driving: are you willing to go for a sedan after all?
Cayenne is expensive to maintain, and as for the Touareg, since it's just few K$ less, I would go for a BMW...