I personally have a KWA LM4, and have nothing but good things to say about it. Its rock solid, shoots well, and feels great. The fps is high enough for Canadian law, but I would recommend getting age verified and ordering in country. While the price in the states may be more attractive, remember that you'll pay tax, shipping, brokerage, etc. And there is no guarantee it won't get siezed even if it is legal. Back to the gun though: from what I've seen and researched, as long as you leave the internals stock, it runs like a champ. It is the single best pick up and play GBBR on the market right now. Its become my primary. Ive never had a problem in long milsim games with it, but I would recommend you at least obtain an AEG as a backup.
Primary: KWA LM4 PTR, Classic Army LWRC M6 A2, Classic Army G36E, AGM/Javelin MP44.
Secondary: KWA Mk. 4 1911, KWA Mac 11, Skeleton Sidearms 8" .357 revolver.