After much research and reading on how to hardwire a radar detector on a F30 I decided to go for it.
I initially wanted to wire it like I did my e90 but this was not possible due to different wiring in the dome lamp and pretty much in the entire F30 platform.
I also got a fair warning from my dealership that if I piggy backed anything to the wiring and if there were electrical issues the warranty would be void. Something I didnt want to risk on my 57k car.
So I opted for the harder, but safer route. The Fuse Box.
You will need the direct wire kit from escort passport wich is what I have, or V1 wire kit, or whatever youre hardwiring. I found my direct wire on Amazon for $8. The next few items you will need you can get at any local auto parts store. Mini add a fuse $7, fuses $5, 16 gauge wire spool $7. I chose black wire to stay stealty but you can pick any color.
Start in the trunk by removing the carpet panel and exposing the fuse box. Work your way toward the front ofthe car on the passanger side.
Youre looking for fuse #146 wich is the RPA and Homelink fuse. You can also use fuse #162 wich on my car is for the 12v accessory, but I chose not to as this is 12 gauge wiring, and I didnt want to lead 12 guauge into 16 gauge. But it will work the same way.
Map light removal credit goes to VSMotorsports, thanks for posting that up in a earlier thread and showing us how to take down the dome lamp.
Good Luck, Take your time, and follow the pictures.
Yes I know its a pain in the butt doing the routing through the trunk and along the panels, as well as time consuming. But this is all we have for now untill someone can find a wire inside the car to tap into, but this is taking chances with warranty as I described earlier. Any questions just PM me.