Thanks John, I am experiencing the same kind of road noise.
Having gone through different tyres I can tell you it has to be sound damping lacking in the floor pan, boot and side wells of the doors.
‘I saw on another Audi forum a chap did it himself for under $1000 and another chap in the EU had it professionally done for about €1500
it’s the removing the seats that scares me, but I am going to see if I can do it with out the seat removal at the front and just the back seats and carpet
I’ll keep you updated