if its the D2, then pry the push button out till it snaps out(you will hear it click) loosen the metal cover thats just underneath the knob... and pull the knob until it comes off.
I did the RS6 gear knob upgrade that was posted on here, it took some time to adapt it... but man it looks nice now, totally upgraded the cars looks:-)
Heres the result(donīt mind the missing door trim, just wasn't finished doing it when taking the picture)
But the knob is beautiful:-) I went with the smooth leather RS6 knob compared to the "golfball" leather RS6 knob
rgds Jake~