I have never tried that particular unit but I have conducted in depth radar detector and radar unit performance tests. I would be very suspicious of any radar detector that was so deeply discounted as Whistler.
When something has a MSRP list price of $329.00 but can be purchased for $117.18, the red flags should go off. To me that means the manufacture can't have more than $25 wrapped up in the complete package.
Picking up a radar signal from miles away is not hard to do. What's hard is separating the real alarms from the false alarms. I may be wrong,,, but I would be willing to bet that you will be plagued with false alarms using that Whistler..