we'll seeing that high powered guns ( KJ M700, Tanaka M700 lineup etc) still make it into Canada i dont see a problem with the power; mainly because they never inspect the fps it puts out. from what i understand, the customs couldn't care less regarding the power. Furthermore the pcs is set to Japan's limits when it comes off the production line so if the customs really want to test it, which they never, it will be under 500 fps.
but all specualtions aside, if you crank it over 500 fps you have a firearm. That fact is unescapable. The part of whether or not the gun can make it across the borders is not a problem; its can you live with the fact you're holding an unregistered firearm.