[Desert Rider]

Darin,
My question about octane was based on my assumption that combustion cylinder pressures would be lower in an engine operating at high altitude, since less air (and so less fuel) entering the combustion chamber. Combustion temperatures should be lower, so internal pressures should be lower, so it seems there is less potential for detonation, hence less need for higher octane.

I will plan to visit with my dealer about octane and PCM (what is this?).

I've also ordered a cat-back exhaust, but wonder if it's needed, since less mass flow through the exhaust than normal.

Thanks,
DR