In addition to the A2 1.4TDI, I run a '70 280 SL, a '86 Capri 280, and a '96 840Ci. No prizes for guessing which is the most economical... Actually, thinking about it, I wonder which is the least economical of these three; I wouldn't be sure; the Beemer does 22.6 mpg average, but I have never measured the others.