Luckily for STERN, I have only ever contacted Jody Dakenberg with a few emails and he forwards the emails onto the appropriate parties.
I have been lucky to have Steve Ritchie contact me directly re AC/DC and John Borg about TRON. I only email STERN if no-one else can answer the question etc. I try to keep any questions/emails up my sleeve, and not bug them unless its a question that will make or break buying a new STERN machine for me.lol    Unlike my posts on here,lol, I have kept my emails to STERN extremely short because I know STERN people are very busy.

Otherwise I use the same email practice with AMD-Bruce if I have a question that I cant get answered anywhere else.
You are correct about the top service from AMD, they are great there. Bruce is a top bloke and buying a machine off him is fun because he has invested alot into keeping the pinball side of his business going, even though they had a few very lean years during the GFC times, yet they have stuck it out, when most would have stopped importing a product that wasnt giving a huge return. I was glad to see the Aussie STERN dealers ride the wave of success with the AC/DC numbers and sales. I think those who bought recent STERNS will and have become STERN fans and will continue to collect the new STERN titles as they come out. Thats good for everyone really.