2 quiestions: does the allroad lowering mod work on the air suspenion, and does XM from the A8 work.
 

on later model Q7's? With the 2 antenna wiring of course.

Re: 2 quiestions: does the allroad lowering mod work on the air suspenion, and does XM from the
 

Yes, the 402 mod from the allroad does work.......do not know about the VM from the A8 though.

What is the "402 Allroad lowering mod"?

if you have the air suspension it allows you to go into the ecu with a VAG-COM and.......
 

trick the computer into thinking the car is higher than it really is. I lowered my allroad this way by 15mm to give it a little bit lower of a stance. This does not take away the ability to raise and lower your car though, but when you do this mod each level is lowered acordingly. I think JET has already done this.