2004 4.4i towbar capability....
 

I'm thinking of picking up a small ski boat and would like to tow it with the X5 but is that a bit much for the drive train or is it capable? Also since mine didn't come with the towbar should I go aftermarket or OEM? I believe they have some that are aftermarket where you can remove the tow hitch and put the cover back on which are just as good? Also is there anything else I need for the engine, transmission coolers, etc? If I remember reading somewhere the factory tow package on these cars has additional cooling or something???

Any advise would be great thanks in advance.

Lots of discussion if you do a search on tow hitch.

The basics:

There is no factory tow package. No additional coolers available or required.

Your vehicle was rated to tow up to 6000 lbs, with up to 600 lbs tongue weight, when using the OE hitch, which was a dealer-supplied accessory. Over 1600 lbs trailer weight (IIRC) requires trailer brakes.

That hitch is stronger than any of the aftermarket hitches due to the way it mounts to the BMW unibody structure. It is not likely to still be available, so you have to find what you can.

Whatever you do for a hitch, you also have to address trailer wiring. The cleanest solution is the OE wiring kit, which came packaged with the trailer hitch kit. It not only supplied wiring for the trailer lights, but it disabled the rear PDC and allowed the DSC to access a trailer stability control mode if the vehicle detected trailer sway. There are simply wire tap systems for trailer lights. Some have been known to interfere with the on board Lighting Control Module, others have been fine.

Jeff