Ooops, I didn't make that clear. With a turbo you lose power at high elevations off-idle, before the turbo spools up. Once the turbo is working, power should be nearly equal to what you'd get a sea level at higher RPM's (say, over 3000rpm). At least it will work that way until you reach extreme elevations, like Pike's Peak, 14,000ft or whatever where the air is so thin there's not enough to feed the turbo intake.
Normally you get power by richening the mixture, turning the ALDA setscrew CCW. It could be possible that turning it in (CW) at high elevations could help. Interesting...
