Or just run it inside the headliner along the windshield, pull the rubber seal off the top of the door frame, and go down into the glove compartment. Unscrew the visor to get you a little bit more flexibility in routing the wire. Might take 45 minutes, including putting your couple of tools away.
'08 Alpine white E92 M3 with DTC--Sold
'12 Alpine white E92 335 Xdrive with slush box
'07 Summit white Chevy 2500 HD Duramax/Allison
'12 Alpine white Z4 35is via EuroDelivery June 4th