i only modified the top of the compression plug/ expander because otherwise the stem would have been impossible to get mounted. i did not modify the c-ring (split ring) sitting on top of the bearing.
This Airwolf frame has some mixed things. Some parts are the same as Cervelo (seatpost clamp, stem,....) and some others are same as Specialized (derailleur hanger, headset bearings,...).
For example, I replaced original hanger with direct mount model for specialized, so I can install GRX derailleur without the connection link.
After replacing original bearings (they´re a little bit crappy) with the ones for Specialized Tarmac SL7, I also replaced compression ring (split ring) with the Tarmac SL7 model I bought in Aliexpress. Cables and hoses guiding is better, headset adjust is now much better and has zero play.
Next step will be to replace the compression plug (the one that needs to be sanded to fit stem) with the model that J&L sells, compatible with Cervelo "C" shape fork. Part is on the way and I hope that once installed it has better grip inside the fork. Original one slips upwards if you apply more than a certain torque to the headcap.