Please note that there's a new toy in town. A thing called 'Spectre' (previously Stalcar, but it was too easily mixed with Stalker, so the Australian-based company changed its name).
This thing is a radar-detector-detector, currently detecting 'ALL' radar-detectors, including BEL's latest, PNI, Cobra and also Valentin 1.. A lot of people got severely punished a couple of months ago here in Finland, because the police had acquired one of these things.
So, if radar-detectors are illegal in your country, please do consider this. See also
http://www.spectre-rdd.com/.