IMO it's only cons in either direction. If anything, police scrutinize these things more cause it's people looking for a pass. The general public probably won't care enough to do anything 99.9% of the time, but why make your car more identifiable or risk it at all if there's no benefit? Why pay more for the plate? Buy a radar detector instead if you really want. Honestly I find mine not even that useful here cause "reasonable" speeding is expected and fine on highways if you're otherwise not doing wild shit. Mine beeps a lot on thickly settled surface roads where I wouldn't speed anyway.