Didn't you get an Owners Manual with the car. I have a P38 (not a Sport). On mine I must press the Inhibit switch on the air suspension to maintain Standard Height when towing.
I presently have a customer car in (P38) which was towing a car trailer with the owners new BMW Estate on it in the UK. He had never towed before and balanced the BMW on the trailer with no forward weight on the jockey wheel (oops) and didn't know about the sir suspension lowering to motorway mode (4 inches lower) after exceeding 50 mph. Result they got to 50 the suspension lowered and he immediately lost control of the whole rig. Went over the armco into a ditch, they got out OK but everything was a right-off. I have the wreck of the p38 which handled the accident well structually (nice to know). We have salvaged the engine (only 30k) and g.box, trans etc. So read that Owners Manual. It should mention what to do when towing. And if not sure take along someone who is experienced. If you have a motorcycle then a good tip is to definately visit the Isle of Man. For the TT or MGP or anytime as its motorcycling heaven. And no speed limits on out of town roads. Good 4x4 club here too.
