On July 16, in the aching torpid heat of the South Florida summer, Terry Whelper stood at the Avis counter at Miami International Airport and rented a bright red Chrysler LeBaron convertible. He had originally signed up for a Dodge Colt, a sensible low-mileage pact, but his wife had told him go on, be sporty for once in your life. So Terry Whelper got the red LeBaron plus the extra collision cov