Some years ago I drove a Diesel Alfa 156 in Italy. Got 35-40 mpg on the Autostrada while cruising at the mandatory 100 mph minimum [hey it’s an Alfa].
I can’t say anything about durability [hey, it’s an Alfa] but in terms of economy and perforance it was a great car.
People are surprised the Jeep can accelerate from 55mph to well past 85mph in a few seconds. It pulls like a mule. I can only imagine how fast that engine in a car built for speed could be. Tunes a little different for HP versus torque and I bet a 200mph car is not unobtainable.
my diesel Golf got 50 mpg. I used to park it in the special slots for energy efficient vehicles that virtue signalers use.