Hello Greg, I feel a bit intimidated posting this since I'm not an expert, I don't race, and I'm not an instructor; I'm just an old guy who likes recreational skiing, and all I have is a small library of skiing instruction books which I enjoy reading to help me with my skiing, so please don't rip me if this post seems amateurish. This is not a comment about your technique (I'm not qualified), which looks good to me anyway, but more related to equipment. In the 'Slow Motion GS and SL' clip watch the motion of your left leg (outside leg) as you enter and ski through the control phase (from entry to exit) of your turns starting at the :29, :34, 1:02, and 1:15 intervals. Is the leg (knee) wobbling in and out? For the most clear example of this go to the "previous thread" video 'Heluva Skier In Slow Motion' at the 1:25 tru 1:27 second interval, the carved turn to the right just before the hockey stop. See the outside knee wobble as you tighten the radius of the turn. Compare this to the other video you have posted of your friend skiing the same run.
Do your skis tend to converge during transition when you're extending and changing edges followed by a lateral movement (not necessarily a stem) of the outside ski at the beginning of the turn? Watch the video sequence shot from the higher angle. What do your tracks on the snow look like? Do they converge at transition and then get wider during the control phase. Do your skis ever feel "grabby", overturn, or respond too quickly?
If any of this seems relevant, a copy of "The Athletic Skier" by Warren Witherell and David Evrard might interest you; if not, just disregard my rambling. It's an older book but you can get it used on the internet for a good price. It's a fasinating book for several reasons, and it's geared toward racers. They emphasize the importance of proper boot alignment and explain the negative effects poor alignment can have on your skiing regardless of how good your technique may be. Don't let the copyright date put you off; I think it still has some relevant stuff in it. The sections on alignment are thorough with some great diagrams and photographs. They expain the effects of being over-canted in your boot alignment (bowlegged stance when your skis are flat on the snow): turns begin with a lateral push of the ski, skis are grabby and overturn or respond too quickly, the downhill knee wobbles in and out in an effort to control an overedged ski during knee angulation. They also list other symptoms of being over-canted in alignment. Don't know for sure if any of this applies to you, just some observations for thought.
You ski too fast for me.