Yeah you would be right on that front. Different cars broadcast different info on the bus, I know for example that my GT TDI broadcasts oil temp, coolant temp, speed, battery voltage on the bus but not the boost pressure as I have a Kufatec E-MFA which listens for these and displays them on the MFA/FIS.
Thanks for the info on your site, I used some of your info as reference in the VAG Blocks software.