Power loss due to altitude

[Brooks Ellis <brooks@fortnet.org>]

        I had a quick question regarding power vs. altitude.
    I live about 6000 feet above sea level, and I have been told that we
have approximatly 85% of the atmospheric pressure that exists at sea level.
Therefore, you need to multiply your car's HP rating by .85 to get its true
power at this level. 
    I was wondering if this would be true for the torque as well as the HP? 
    A side note : apparently, turbo cars are not affected nearly as much -
they still stuff the same mass of air into the engine.. I would imagine
however, that they still take longer to spool up, and of course, have worse
off-boost response. 

    Audi content - I went snowboarding this weekend, and, as usual, the good
'ol 100Q kicked ass up and down the mountains.. Even so, at 10,000 feet, the
performance leaves something to be desired.. ( that is the root of my
question ) It would be cool to have a '91 20v turbo or an S4 up there.. blow
away new Camaros and anything else normally aspirated.. Chip it, and REALLY
fly. Fly up I-70 at 120 miles an hour..wow.. The Coloradobahn. 

Brooks