It’s really easy. Once BMW FS has your title, just create a listing on SAL. Post the pretax payment and the other particulars in your listing. Probably ask for no down payment. You should have a few bites within a week. When you have someone ready to move forward you call BMW FS and inform them you want to initiate a lease transfer and give them the transferee’s info. Then the transferee gets sent a credit app, once approved they get sent more documents to sign and then before you know it within a couple weeks you’re handing the keys over and you’re free and clear.
I would definitely do this if I were you. @IAC_Scott is right, perfect opportunity to wipe all the neg equity at once and start with a clean slate.