The A4 B6/B7 units (8E0) and A3 unit (8P0) do use speed over CAN and no dedicated wire anymore. The unit calculates based on the speed data the required audio level adjustment (non-Bose systems only). Bose systems do not use the speed info anymore, they measure the acoustic and adjust the volume accordingly. The v-pin can only be used with 4B0 units but not with 8E0, 8H0 and 8P0 units.
I haven't actually tried to disable Bose by specifying anything but 255 in channel 008 but the TB about the AudioPilot issue explains how to change the wiring to turn off the AudioPilot. Therefore I suppose changing this value on a Bose system won't make any difference without changing the wiring too. You can however change the GALA characteristics for non-Bose systems.
So, if you have Bose, leave it at 255. If you like GALA on a non-Bose system, choose 1 to 5, or turn GALA off by setting a value of 0.