Non prohibited accessories are fine to order from anywhere. The real question is, what else do you want? Good customer service but pay a little bit more? Crap customer service but cheap? Fast shipping? Free shipping? Shop around a bit.
Try places like Redwolf, eHobby, WGC, all those other Asian retailers etc. Then locally in Canada like at real steel gunshops (might be a bit expensive from there), Canadian Tire, surplus shops, airsoft shops in Canada, etc.
It will be fine to import. Only problems you might have is ordering stuff from the US and the item in question being under ITAR restrictions (US export prohibited).
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE