Post restante in Asia
I often used Post Restante, which is a service of all post offices worldwide (if you're unfamiliar with it, then is for when you don't have an address, the post office keeps the mail for upto 1 month and you can pick up the parcel/letter at your convenience.) I used it several times in Thailand, Nepal and India for smaller bike parts and even a new credit card (that expired during my travels). I always got my package even in smaller towns.
I think the trick is to choose a small but well connected town and the always ensure you have the right postcode or it will cause you problems. If you can get the town and postcode then it a great service as you can exploit it by sending parts (ie. internet ordered) to a town in advance so that the part is there when you arrive. If you have to wait then drink some Everest or Sherpa
Use the following format:
<Country> <Post Code>
In the long run it'll cost you a lot less than DHL but of course with postage there is always the risk it will get lost or damaged. We were lucky and we never hand to pay any taxes, but the parts were'nt more than small parts, ie. spark plugs, oil filter, air filter, tools, brake pads etc.