THE STATE EXCISE TAX ON AUTO SALES GOES FROM 3 PERCENT TO 4 PERCENT ON MONDAY. SO, WHAT DOES IT MEAN TO YOU? CHARLES HENSON IS THE PRESIDENT OF THE NEW MEXICO AUTOMOTIVE DEALERS ASSOCIATION. HE SAYS THE INCREASE ON A 20-THOUSAND DOLLAR VEHICLE WOULD MEAN THE TAX GOES FROM 600 DOLLARS TO 800 DOLLARS.…… MORE