It appears you are going to have to have a custom trailer hitch receiver fabricated for your 2015 BMW 6 Xdrive as there is not an aftermarket option available. We do have the Weld-On Receiver # E17 which will help in the fabrication of a receiver for your BMW.
The ZCI Circuit Protected Vehicle Wiring Harness # 119250KIT will allow you to add a 4-way connector to your BMW without having to splice into your factory wiring. This uses sensors placed over the vehicle wiring to detect when... view full answer...
We do not have any trailer hitch fits for your 2008 BMW 650i convertible. In fact we have none for any 6-Series models. I did check directly with both Draw-Tite and Curt and confirmed that there are no hitch fits for the vehicle. That is the bad news.
But the good news is that we do have confirmed trunk-mount rack fits for your 6-Series convertible. These are shown on the linked page and they include 1-, 2- and 3-bike options from Thule, Malone and others. Included are the unique high-end... view full answer...