I think K40 is the brand not the exact detector. If you are talking about the remotely mounted detectors that have to be installed by a K40 dealer and cost ~$1000+ I have read good things about them and for those people with tint because the sensors are remotly mounted your tint will not get in the way.
If you are talking about a K40 brand detector that is shaped like other detectors I have not heard anything as good about them.
