Small update. Changed the throttle actuator as it felt like either the tps or actuator was playing up at mid range rpm, and cleaned the ICV while there. It was pretty clean to start with and so were the throttles. It goes a long way keeping the motor clean and it maintains its power and cleanliness more consistently once done properly.
I'll see how it runs over the next couple of days to confirm whether this was the solution or not.
Engine oil also still looking clear and gold

Gotta love frequent oil changes.
Oh and I didnt take pics but changed the gearbox oil as well... MTF-LT2 even though it shows MTF-LT1 on the G420. Feels nice and slick with the short shift kit and shortened 6spd shifter.