Originally posted by Deronn_solo
Kinda a messy stance, given we know Vader's ower grew throughout the decades, to where he received a solid upgrade after ANH, and further increased that power in RotJ, where he reached the pinnacle of his power.
We can't really conclusively prove this either way, honestly.
The gap between Muur and Vader had to be have been noticeable for him to be fantasizing over Muur's power to that extent. He even considered Muur potentially being another master to him, which means that Muur would've had to be above him by quite a noticeable degree. Even if Vader grew vastly, I doubt he would've surpassed Ragnos, who was more powerful than Pall, who in turn, was more powerful than Muur. And Kun's more powerful than Ragnos, so do the math.
The only showings I find suspect are his Force Blast feats; I have no problem with any of the others.
So you take his spirit feats? That should be good enough, tbh. Though his Force Blast feats aren't that unbelievable at all. Assuming he has his trinkets here, which the OP says he doesn't but we can discuss a bonus round where he has them.