Say i get 3000 per month, but no housing and my rent is 1000 - does it make any difference to me in terms of tax/foriegner housing costs etc to pay the rent myself versus taking 2000 per month and getting 1000 worth of housing supplied by the company?
Above info is correct. It is tax efficient for the company to have residential lease contract in their name. However the price you pay for accom will increase as the landlord will be liable for tax on the monies they receive from the company. Swings and roundabouts!!!!
If I were you, negotiate your salary based on net income - stipulate that all local taxes are the responsibility of your employer. Don't even ask about how much they need to pay (or pay off) the gov't.
That way you'll avoid all the red tape and let your employer take the risks of the tax situation of VN. If I were I would put your employer between you and every gov't requirement. Let them deal with the application for all the visa/resident permit as well.
They couldn't pay you enough to deal with it all on your own.