Just got off the phone with him. The power up to 5k is VERY happy. This may be a simple case of time to learn for the PCM for the higher RPM fueling at WOT.
He'* going to give it time on the 93 octane in the tank before boosting the octane further. In the meantime, he'* going to do a top-end seafoam to eliminate any carbon deposits acting as glow plugs.
I gave him a good octane mix formula for Toluene+93 octane that will bump him to 96 octane if he needs it later.
(Giving the update here because I firmly believe that 'offline' troubleshooting help is very important to the topic and forum, which is why I generally discourage it in the first place)