Altitude and Prop/Motor adjustments for ski boat
 

Went to Lake Tahoe last week for a few days of skiing. What a view of the
lake from the Homewood ski resort; a mom and pop operation with the best
view in town!

Given that my boat has EFI, will the altitude reduce the power significantly
when I bring the boat up this summer? Significant would mean enough to
justify buying a second prop for a once a year altitude adjustment?