I live at 7000 ft and my LME 91 tune seems really strong. Altitude is funny but the biggest issue I have had, and not just with a tuned turbo car, is with throttle response.
We have family in Kansas and when we go back that's one thing I have noticed is the much, much improved throttle response I get at sea level. This is obviously normal behavior from a naturally asperated vehicle.
I haven't been back to Kansas in the tuned lincoln and I'm not sure it's possible but it seems like throttle response could be better at altitude in a turbo car? Maybe LME can chime in on this.