Former F1 champ Stewart looks at future of racing.

Byline: Mike Brudenell

DETROIT _ A wee bit older and a couple of pounds heavier, legendary racer Sir Jackie Stewart is a happy Scot these days.

In town for the North American International Auto Show, Stewart, winner of 27 Formula One races, knows he's also lucky. In recent years, his family, including his wife, Lady Helen, and son Paul, have survived bouts with cancer. Last November, Stewart himself was treated for a melanoma on his left cheek.

"You could say I've had a wake-up call," Stewart said Tuesday. "I'd advise people to have regular checkups with their doctor. No one is bulletproof. We don't walk on water."

Stewart, 63, had the …