I had a rabbit as a driver....
top speed about 70mph felt like it needed another gear.
I averaged 53mpg or 500+ miles per 10 gal tank of fuel.
I put KYB gas struts at all corners, made the car handle great.
I also put two replacement engines in. Due to overheating.
In hindsight, I believe this is due to the cloth wound hoses would steam the coolant out, even though psi test were normal and no leak visable.
Diesels run about 225F
I still concidered it to be a FREE car, paying for itself through fuel savings

And stick with a radio, it rattled two high end tape decks apart