Just as a reference for those who want to stick with the fuse box under the dash. Using fuse #3 will give you constant power and fuse #7 (which was empty for me) will give you a semi-switched power. My yellow (constant) is on #3 and my red (switched) is on #7. The camera has parking monitor now and as soon as you open any door or the trunk it starts recording. The recording will remain on even if you stop the engine and lock the doors for x number of minutes then turns off and will be in parking monitor mode.

It is probably easier to wiretap into the overhead wires and it is kind of a pain to access the under-dash fuse box. There is also no obvious ground available so you have to drive a small screw into the metal frame under the dash.

This is for a 2012 x35i.