We've used a weight distribution hitch on our previous X5, but when we picked up our new RV travel trailer (3800 lb dry weight), we had to sign a waiver to the RV Dealer because they said that BMW does not recommend using WDH because it can cause damage to the unibody frame, and we insisted on using the weight distribution hitch for safety and towing comfort reasons. We are close to 50% of what the towing capacity is of the X5. Can anyone shed some light on this situation? Checked with BMW Dealer but it seems that they sell so few X5 with towing package, they didn't have much info to add to the RV Dealer's claim. Appreciate any info you can share. Thanks all !