Howdy!
Couple things thought I'd share: If you bought the Pirelli "Verde" edition tires; well, they are simply not very good tires for this car as use a hard compound and very bouncy. The Scorpion PZERO A/S + is the correct Pirelli tire for the Q7 for high-performance all season capability. Since you have 90k miles on yours, you need to be looking at servicing the fluids in your complete drivetrain, if not done already. This means tranny, transfer case, and both differentials need fluid drain/fill services performed. The diffs and the transfer case are pretty easy to service as a DIY project if you have ramps or can elevate the car a bit (air-susp and a high curb will do), but the tranny i paid a shop to do and just bought a kit online with new OEM filter/pan seal, and bought the trans fluid in bulk (liqui-moly on Amazon in 20L jug). Just be sure to get the 100% correct fluid type for the component being serviced.