If the Golf TDI only gets 40MPG it has too much engine. I don't mind a slow car. I grew up when zero to sixty in ten seconds was pretty fast. I'd be happy with 0 - 60 in 13 seconds or so. I drive an old Mercedes 190D now that probably doesn't go nearly that fast. Back then there were plenty of cars with small gasoline engines that got 40+ MPG. Toyota Corolla with the base 1.3 liter (IIRC), Datsun B210 1.2 l, Honda Civic got 50MPG as I recall. The cars were all fun to drive.
Not exactly 40 mpg? http://thinkblue.vw.com/5882-mpg-guinness-world-record-set-by-jetta-tdi/

