Thanks for the reply.
Is this the bit from the Quick links you are refering to ?
'Also, it has been proven that CAN gateways can work across the A4/A6/A8 model range (a C5 A6 unit has been tested and worked in a B5 A4/S4). The reason that the VAG part numbers are different is because of the model-specific mounting bracket. Per Jon Lofquist: the 8E0 unit TMC will work with any of the nav+ units for CAN Gateway function. I have tested my 8E0 919 895B TMC with 4B0, 4D0, 8D0, and 8D0 navis.'
I guess this means that an 8E0 TMC will work in my A4 B5 for the instrument cluster. But will it also work for Dynamic re-routing ? Or am I misunderstanding something ?