Wait for the M4.....and keep the car for now.....
I love it when people say that they are going to keep their car's "forever"....
Current: 2016 F10 535i xDrive AW w/ Black Dakota, ZMM, ZCW, ZDA, ZDB, ZPP, 688 & Black Grills.
Retired: 2011 E92 M3 -AW
....ED April 29th, 2010
Retired: 2007 E92 335i -Space Gray.....ED Oct 19th, 2006