Gremlins and findings after drivetrain upgrades
 

New Clutch, CMC & CSC with TK Titanium knob:

Shifter is more notchy than stock, almost like a short shifter. Takes more effort at high rpm to bang through gears. This is mostly the knob. I was missing gears at high rpm when granny shifting. Shifts were smoother with the clutch pedal depressed half way. It got even smoother when no lift shifting. I'm still looking for that sweet spot in the clutch pedal the car likes. I had someone else drive it and he banged through the gears like a hero. I was in my passenger seat with my mind blown.

Conclusion: Driver mod. I need to fix my self.

Random brake light coming on with new differential upgrade:

So when I'm full throttle, there's a mild resonance I can feel and hear; over 6krpm. And I notice my brake light lights up. It doesn't stay on, just momentarily, maybe the sensor vibrating from that resonance?

Yaw sensor light turning on under hard acceleration with anything over light cornering:

This has happened twice in two days. Wondering if it's the diff sensors, shafts moving, not sure. It turns off after I shut the car down. I still don't know what it is. Need to log the code when it pops on again. Not sure what's causing this one.

Any ideas?