Well, the 1.8 at 5k...................i think that you will have trouble there. The new DP kits are lighter due to laser cut parts, and here at sea level, the 1.8 is plenty of power. At 5k though, I think that you would not be impressed. The only advice that I can offer is the use of a ZDZ 50 gas. Would be more than enough power here, but Im not sure what it would be like up there.