Mike1234,
You seem to be doing everything all of us could think of. I was thinking along the same line as Skunkboat that perhaps the listing at rest is not related to the heeling over at speed. If so, the at spped isue has to be either excessive drag on one side or excessive thrust or thrust direction on the other side. What I might suggest is running the boat on each engine separately ( opposite motor out of the water to see how she handles. What I would be looking at is difference in magnitude of heeling on the two sides to try and isolate the side causing the uneven thrust/drag. I would also closely check the motor angles (tilt) while underway.
Do you have a bow thruster?
Did you check the bottom of the hull for things that could add drag? Is it possible that a trim tan hinge section has broken, come loose or moved?
Do your motors have trim anodes with fins?
I am sure you will figure it out....eventually