I maidened mine yesterday at 6000 ft of actual altitude, higher density altitude cause it was so hot.

Took off great, a little long. Flew great, nice and level, very high. Landed great, perfect flair. Only change I did was raise the flaps to mid-position. I am using the stock prop, engine, etc.

Not sure where all these issues are coming from if I can fly it at such a high altitude with literally no major issues, and one very minor one.