Low noise kit from PINBALL CENTRE is remarkable.
Basically it is a padding of what appears to be a thin, high grade silicone composite that it is pre cut to fit between plungers and coils stops, end of plungers and where the sling arms hit the play field underneath. Due to copyright ( I guess? ) I won't give all instructions. Just a sample.
Put it in WNBJM as it is extremely noisy machine, due to the air gaps around it's unique cabinet and it is just AWESOME the difference it makes to say the least. You do lose a smidgen of power, but on a SPIKE system you can bump up power to the coils a bit anyway.
Pinball Centre didn't a recommend a glue to use, so I just cleaned with isopropyl and stuck down with UHU supaglue. Lets hope it lasts.
You will not believe your ears when you hear the noise dampening of the mechanical clunking.
Will try in another machine, even an EM and suss it out.
Happy mothers day to all the Mums.