Just installed a made to measure resonator. Resutls : drone killed
I got very very important and annoying vibrations / droning waves on all the cabin, some plastics vibrated and i felt them on my seat between 1500 and 2200 RPMs. Everything is now OK, highway cruising is now possible !
The sound is now a little bit quieter and has changed between 5000 and 7000 RPMs ( less rough ). I was feared to loose this rough note but i had to make a concession such the drone was present.