Originally Posted by Bubajay
I know this has been posted before but I just watched it again for the first time in 2 years and it made me LOL
17.2 mpg = Prius
19.4 mpg = M3
That is a great piece, and quintessential Top Gear stuff - both entertaining and educational.
First time I encountered anything like this was a piece in "Car Life" magazine way back in '71, comparing everyday Buick Skylark 350s, one a high-compression 1970 model, and the other a '71, set up to run on the then-new (and mandated) no-lead regular fuel.
Result: Just what you might expect, given the Top Gear piece. The 1970 car was of course quite a bit quicker than the '71, but it also got definitively better mileage throughout the side-by-side test - enough to more than offset the price-per-gallon difference between the fuels.
Primary difference: The '71 had to gas it harder to stay with the loafing 1970 car, pretty much like the M3-Prius story.