Yep, this is absolutely true. Diesels that are babied around town run like crap, get bad mileage, are slow and smoke.

Highway diesels run great, especially ones that are driven hard.

I admit, I do drive my car -very- hard but I have had zero problems in 45,000 miles with the drivetrain, does not smoke, starts right up and runs like a dream.

Drive 'em hard!