Towing heavier trailers, such as a two-axle caravan is no issue for the BMW X7. There is plenty of power from the engines and it’s a very stable car, so you will barely notice there’s anything behind ...
The BMW X7 is everything a big luxury ... while it offers fractionally quicker acceleration than the 40d (0-62mph in 5.8sec) you do need to rev the engine a bit harder to access that performance.