Hope you get it sorted mate, sounds like it almost needs a thicker release bearing like the orc/blitz kits use. by the way the sugar cube is different on older gearboxes and is just a plastic bit like above which doesn't seem to wear.
I do agree with some of what you say... but I also find it very ironic you're continually moaning about people not wanting to pay for the things you're selling when you're basically trading unofficially...
Like I say it's easier to install an HKS or similar actuator (single port) if you remove the stock solenoid - a lot of actuators will be bought second hand too so won't come with the tee piece needed to plumb in the stock solenoid.... so people don't bother.
Why keep it when your foot controls how fast you want to go?.... Even with a proper ebc I never used the low boost setting. With an HKS actuator the stock hi/lo solenoid doesn't vary the boost much anyway and it's easier to install if you exclude the solenoid, that's the main reason to remove it on a GT.
The pitting is det marks, I've a head here the same. Most will come out with a skim but I wouldn't worry about the rest, not gonna cause issues running. I'd lightly dress the cam cap but don't take any material off the bore.