I remember I talked to l o c k h a r t tactical not too long ago about their Kpos or Roni kits I don't think they mentioned restriction or law since your pistol is already restricted.
You can compare price vs shipping with them to see how much you save on the US deal (yes usually US is cheaper in every way).
Btw, which kit you are looking at? Most is just a fancy shell with extra stock and handle but I like the one with the 16" replacement barrel. IMHO only that one is worth the money. Make sure you review everything before pulling the trigger. With that price for the Roni kits I ended up getting a JR Carbine instead for a little bit more.
Have that said, how exactly do you plan to 'bring' it across the border?