Long time lurker, first time posting here now that I've upgraded my A1 to an A4 2.0 TDI 150PS Black Edition.

I have something I was hoping someone here could help me with as I get used to the new car:

I have read a lot about the TDI Engines online and seemingly the recommendation for these engines appears to be to rev to 2500RPM when cold, 3000+ when warm and when at a steady speed make sure to choose a gear that keeps the engine speed between 1800-2000RPM to make sure the engine sits in the most efficient zone. Do others here agree?

Which leads me to another question relating to this. The indicator on the DIS seems to be massively optimistic in terms of when it wants me to change - it suggests I change up when the engine speed is already quite low (say 1700RPM). If I follow the advice the RPM in the higher gear can be around 1300RPM which seems really low, even the manual says to keep the RPM above 1500! I have read that it's not good for the health of the TDI Engine and turbo to operate the engine at such a low RPM, so should I just ignore the DIS indicator?

In fact, can the DIS indicator be turned off? I can't seem to find the option for it in the car settings, and it's forever moaning at me for not changing into higher gears at ludicrously low engine speeds!

Thanks in advance for all advice.