Yes you‘re right when you say they are all old now and often treatet hard
But BWA‘s are old as well and i never have had such issue with them.
For example when you give a bit more boost on them and let i-limit untouched, they all overshoot at around 0,3 bar till the PID catch it back. On AXX it never does from my experience. It stucks directly at 0,95 bar.
So if you or anybody else here had ever managed to go higher on this Engine with stock components, let me know and i‘ll do more reserche on this