They don't usually install "spyware", what they generally do is simply leave some traces to the system (files, registry entries or the likes) to indicate that the trial has been on the machine and its expired. I read the description of the program on their website, though, and apparently it only routes your traffic through proxies - something you can do yourself without any extra software (I don't know if the proxies offered with the program are better in any way, but I personally wouldn't pay for it). I think it's against the forum rules to offer help to circumvent the trial, though.