Thanks Rich for your reply and suggestion.
I have spoken to Customs & Border Protection and they say it's very straightforward and very popular, many people are doing it, especially with the difference in the dollars.
I can refer people to various links but the bottom line is:
The buyer pays me and I give him the ownership document AND a bill of sale.
The buyer present the car to CBP and declares themselves as US resident and wish to do a personal importation.
He shows the two docs I gave him and the agent has all of the forms to fill out with or for him.
A car 31 years old does not have any DOT or EPA issues at the border.
Duty will be charged at a rate of 2.5 % (two and a half only), and they accept cash or credit cards.
That's it, they rest is the same as buying a car in their own home state.
Namely, you should have with you some license plates OR temporary travel permit from their home state.
Of course, insurance on the car should be arranged for.
Any other questions, I'm glad to help out with.
On this forum, or at www.pcarmarket.com