Originally Posted by
Pigmy Pony
Grant, I'm hoping you meant 50 mpg, not mph, otherwise it's not a very good case for diesels! Unless your motor was made by John Deere or Massey Ferguson.
My definition of performance cars (diesel or petrol) is quite simple. If it has been tuned for performance rather than for economy, it's a performance car. Much like hifi - if it was made with the intention to provide a faithful reproduction of music, it is hifi, regardless of how much it costs.
But as with many other things, I could be wrong!