They last forever. I have 295K on mine and still running fine.
now about adding a/c... i heard that the evaporator is close to an 8 hour job... is that true???
All in all it is a great vehicle. Love the way it handles and I'm currently getting 700 miles to a 14 gallon tank which = 50mpg. Also when I want to get up and go there is plenty of power to move, just don't be to close if you don't want to breath the smoke, it isn't to bad but you can see it under full throttle.