if it's anything like the 8P one then STAY AWAY
i've never owned one but a member of another forum did and he said not only was it rubbish but it jammed in his dashboard and he had to cut it out again to replace it. their customer service is also meant to be lousy, and apparently the photos do justice to the real product.
RNS-510s are not that expensive (and they're cheaper than RNS-Es despite being MILES better). just save a bit longer and get the real thing