I have a cousin in the shipping business. He put me onto a company called Vanguard Logistic, Direct Container Lines, NACA Logistics in various parts of the world and their organization. They did not go on weight, but on linear dimensions (volume). I dropped off my own crated shipment of books and clothes in Newark, N.J. for shipping to Doha. It took about a month by ship (Ramadan slowed it down). My shipment was about 3foot, by 3 foot at the base, and 4.5 feet high. It weighed about 220 lbs They charged me 180 USD and it looks like I'm due to pay about 200 USD in customs fees. Don't know if there will be further tariffs or tax on my personal belongings. It is in the port right now, and I have yet to get word on how to pick it up.

I don't know anything about vehicles or taxes/customs on them.
The contact to discuss this if you think this is useful is:
DCL
Freight Systems Co. Ltd WLL-Doha
0119744660870
[email protected]
See what they say.