BlenMounts are very clean, I had one on my V1 Gen 2 in my Audi S5 before moving to the Model 3. It has a mirror power tap available as well, but unfortunately there is no switched power in the mirror like a lot of other cars. Some people just remember to turn the radar off or remove it when not driving to avoid the battery drain. Others hardwire it down in the footwell to switched power. Works well.
I’ve run a few versions of the V1 Gen 1 in five different cars and always used the suction cup mount in conjunction with hardwiring for power in some way (tapping mirrors or sunroof controls, fuse block add a fuse, etc). For now in the Tesla I’m just using the 12v power in the armrest to power the V1 (and the Bluetooth LE module the Gen 1 needs to run V1 Driver). For a mount, I’m just using an inexpensive suction cup phone mount someone here posted about.