Resurrecting this old thread to maybe help somebody, because I didn't see the Model Y hardwire threads were converging on an easy-to-wire positioning. My approach & results:
1. I'm finding the MYP is too fast and too quiet not to have a radar detector in it!
2. I don't like mounting options that block my view. While I think the Blendmount below the mirror or the mounts that position the RD above the screen can look beautifully integrated, both those approaches position the RD in the narrow eyeline below the mirror and above the screen. My preferred location is up and to the left of the mirror/camera placement. I just use the normal suction cup mount, which others seem to have trouble with, but I find if you clean the glass and the suction cups before installing, it will literally stay there for many years until the suction cup rubber yellows/hardens.
3. I use a V1G2 + JBV1 combination, and my goal was to run a direct wire across the top of the windshield and down the driver's side A-pillar to the driver foot well. It turns out you can easily do that without removing the headliner or A-pillar trim.
The key point is at the footwell, is there an easy place to pick up switched 12V power? This Model 3 video was intriguing to me, because it shows where to tap into the 12V accessory port (cigarette lighter socket) in the center console without having to go all the way to the console and take that apart. Same wire in a far easier access location.
What seemed to be an open discussion was whether this 12V power source was switched or not? The answer is yes, but it stays on for several minutes after you leave the car, so to some installers it looked like it was not switched. It is in fact switched in the Model Y, and presumably the Model 3.
I just used a normal wire tap in Valentine's direct wire kit with this wire and it is working perfectly.
