I've considered that, already. The question is whether the volume set on the amp will remain at that level forever. Having to set that volume every time it gets lost would be a problem.
Another concern is that I will have to have it set to the max level I expect the volume to ever be, and that means that the pop/scratch sound DUDU7 makes on reboot will be played so much louder. I don't want that either.
Actually, any noise would be amplified all the time, which would probably mean that I'd have to live with a constant background noise, and that the signal to noise ratio at low volume levels would get rather bad.
Minor loss of volume sync I can live with. Noise would be much more of a problem.
Oh, there's also a question of whether I'll be able to adjust the amp volume if I select a car model without amplifier. I think among the models I tried, the non-amp ones just didn't even have the amplifier section in the car settings, and that's the only way to set the amplifier level. I could set it using the current car model, then change to no-amp model, and then hope really really hard that it would never change. I'm not that adventurous.