ok i dont drive for wse but i do have an 2013 prostar with the promax motor. my comp has it turned down to 62. my impression coming from a 09 century, is it drives like a car. from steering to breaking it "feels" like a car not a truck. lost some storage in it as well. the battery powered apu works as well as expected, nothing will keep you cool when it's 105 outside. (but thats nothing a gatorade bottle wedged between the throttle and the break pedal to over ride the auto shut down wont fix..)
found a glitch in the computer limiter, if you can get it over 66 keep your foot to the floor, it'll keep going for @ 5-10 miles at that speed. same thing if you hit 68 going down hill. keep foot to the floor and it'll hold that speed for about the same distance. now if you hit 70, hold on cause it'll run pretty much as fast as you wanna go. ( i had way to much time on my hands coming back from Cali when i noticed this.)
anyway, it's a decent truck. good luck if you get one.
I am in a new one now, have been for a bit over 3 weeks. So far everything works. My main problem is the weight. We pull so many heavy loads and most of the time I can't fill my tanks. It is a pain, but I like driving a truck that has don't smell.