I tow my Discovery which is about 2100kgs loaded without a WDH and I find it pretty stable. All new GC's have trailer sway control. I averaged 14.2 when towing through the Snowy Mountains recently. Water temp gets high on climbs which numerous owners have reported but I don't think anyone has killed their cars yet. Go the CRD. Also I have the quadralift air suspension which keeps it level. Overall I'm really happy with mine.
I can tell you this much it doesn't work all that well....