Engine lifespan and transmission lifespan and fuel milage

WIll there be a estimated total lifespan number on motors and transmissions, Like a Honda Accord we know can go 250,000 miles without many issues. Will there be certain problems with each model car like mustangs have bad ball joint issues or Volvo s60s have valve cover issues, Saabs have window motor issues? Like if my MTBF is 50k miles what is that going to mean in the game the engine only goes 50k miles, or is that when it needs to be serviced? Will there also be fuel mileage numbers in MPG?

Yes.

MTBF is on average how often something needs fixing, even if it’s just some minor issue.