Load of suggestions
So, my suggestions are; being able to choose diesel, gasoline and lpg. Being able to make hybrids ( and if its implied, using two non-electric engines *inline 3 for city and v8 when racing or freeway*).Ability to choose rarer engines ( w, vr, shaped, rotary, more than normal cilinders - I'd love to see a w48 engine). Ability to dual charge ( using both super-, and turbocharger ). Multiple axles. I think that's it.