Fox889

Is self levelling common place on a 7 series?

First time new bug on here so please have patience with me! Looking at buying a Jag XJ 2.7tdi or a 730d, either will be probably be around 2006/2007. The reviews on the BMW are far better than the Jag but my only concern is, that I haven't seen many 730's towing large twin axle caravans! Do they suffer a 'saggy #####' when towing? Are 7 series of this age fitted with air suspension or air shocks? Lots of questions, really appreciate your help with this. Nick.