We have a few Ligier and JDM "cars" come in for maintenance at the dealership, they usually have Lombardini or Yanmar 2 cilinder diesels in them. Usually they do little mileage but the last one 60,000 miles on it, at a top speed of 30 mph that's at least 2000 hours. No signs of wear on the engine.
Top speed and weight are limited as you can drive these things without license.