From a buyers point of view. I have bought a lot of parts from the states, (i live in Aus), ebay, Miksxs, and xs650.com and have had no problems recieving parts. USPS is the best pricewise, reliability and the time it takes to get here. I have bought some large items, a set of front forks with the tripple clamps and a set of exhausts for a TXA, ( Mufflers and headers, heavy little buggers), without any problems. If you can get stuff into a flat rate box it is good as the cost is for the box.
As long as the parts are marked as used and less then $1000.00 there are no taxes to pay sending stuff here. Parts would arrive from Mikesxs in 10 days but sometimes parts have taken 2-2 1/2 weeks
Go to the USPS site and look up the scheduals for international and the only way to send stuff overseas is by "Priority Mail International" It may be a little bit more expensive but worth it as it has tracking as well. I would insist on the sellers to do it that way even though it cost a little more