Spuzz, with respect to your relatives, why can't she use a slightly cleaner alternative; a wheelchair?
A wheelchair can't easily make it up a 6% grade, and she doesn't qualify as significantly handicapped to require an electric wheelchair covered by the government. She'd give herself a heart attack in ten minutes if she used a conventional wheelchair, and we can't afford an electric wheelchair. =)
Because, it's fun to have 500 hp. Don't ask why, it just is. >_> That, and I love the style of the old cars.