Welcome to Vacuumland. Here are my thoughts.
If any rug is not permanently attached to a hard floor by rubber grips underneath and inclined to move when an air driven turbo brush moves on it, the same will happen with a power nozzle floor head.
PN heads are substantially better than air driven turbo brushes but they are usually heavier than the air driven turbo brush.
The D series by SEBO is generally quiet BUT I also own a Miele S8 and it is quieter than the SEBO.
I also have a D2 which is a non-electric version, but I also have a K3 Premium with PN and a SEBO Felix that uses the same ET-1 power nozzle. When the PN is switched on, it creates extra noise, so you do have to compromise on that, and would be louder than the Miele S8310.
I don't believe much in decibel ratings - they are not usually tested in a home but in a sound proof test laboratory where ambient noise around you isn't taken into account.
I have wool carpets - my Felix is fitted with a delicate brush roll. It cares for them better, so yes the delicate brush roller would be better.
SEBO's new EU range related vacuums haven't come onto the market properly yet - as soon as they come onto the market I would expect them to be quieter despite what the decibel levels says. I intend to buy one of their newer ones this year to see if there is any different noise wise, but I can't relate anything at the moment.
Personally if all you have are wool rugs, I would be inclined to just buy the Miele turbo brush for the Miele S8310 and be done with that. After all, it seems silly to have to buy an entirely new vacuum cleaner - and the brush rolls on Air driven turbo brushes aren't very abrasive.
