I've had numerous people ask me how I hardwired my V1, and I've seen even more people asking how to hardwire their detector. This DIY should work for any radar detector. If you don't have a wiring kit, you can cut the end off of your 12v adapter and there should be a red (positive) wire and a black (ground) wire. Use the red wire to piggyback the green/white wire in the DIY and the black one as your ground.
I used this DIY:
http://www.e90post.com/forums/showthread.php?t=97545
***Important***
There are 2 banks of wires with a green & white wire. Make sure to tap/piggyback the green & white wire in the bank of wires closest to the driver's side. The other one doesn't work. And to ground your detector, you may have screws above the console, use one of those. If you don't, you can use a self tapping screw and screw into the roof right beside one of the small holes already there. I did it and it works fine.
I take no responsibility for you messing up your car