Diesels, boxer especially air boxers and steam engines have been lifelong favorites of mine, the engines have real soul. They may not be the fastest but they have some wonderful mechanical sounds.The pre DPF, DEF diesels were the absolute bomb.
Once the emission stuff started the diesels turned into a pain. That said I still loved my sprinters.
It's probably different for you because you can basically do anything where I'm limited to basic stuff.