Hey guys, it comes with an on/off switch that you can install anywhere in the cabin.
I got it installed and tested. The guy who did the install is really good - he knows everything about the laser and radar guns that are used. He'll drive in NJ/NY, etc. He has a 335i as well. He will test it for you too.
If you guys are interested shoot me a PM and I can give you his contact info.
As for the install, the heads just mount vertically in between the grill: no cutting needed. It's a pretty clean install.