I had a 400h before the 450 I have now, fitted the tow bar to the 400 myself, a bit of a fiddle with the wiring but managed it. I had a Westfallia detachable bar fitted to my 450 by PF jones, they did it on my driveway. Both vehicles tow my 1700kg caravan without any issues. As has been said fuel consumption is not great while towing but this is offset by good economy (for a vehicle of this size) when not towing. I've had three discos a Merc ML270 and a Jeep Grand Cherokee before the Lexus and The Lexus are the best overall.