Thanks for the replys Everyone! Keep 'em coming!

Somewhere I saw numbers about the reduction of power as you gain altitude but I can't remember where that was. Just as a WAG I'm going to say that from sea level to 5400 feet the power reduction is aroung 15-20%.

I've been looking at the Mark 1.8 and 2.1 on Dave Patrick's site. Lower compression, more nitro, etc. that's all good. Seems they've solved an issue with the carb as well. The blue head looks really cool too (not that it'll be seen). Speaking of that, do any of you know if the 2.1 will fit inside the cowl? I'd like to keep everything inside if at all possible.