If you refinance as a purchase, and assuming you get a good rate, you can always trade it in on a much better deal. I would do that, rather than pay this ridiculous lease payment. At least you will gain equity...especially since the 328 will hold its value relatively well after the 1st 2 years.
Gone but not forgotten: 2008 BMW135i Vert
Gone but not forgotten: 2011 MB C63 AMG
Gone but not forgotten: 2011 BMW z4 3.5is
Added: 2015 Z4 3.5i