Morris is right - I am doing the upper chain rails. The passanger's side has been doing great, but the driver's side is fighting me. You're right - the timing is computerized and cannot be adjusted at the distributor.
About doing it without removing the distributor - you really can't get the pins on the inside side of the engine out without pulling it. Especially since the pins are harder to get out on that side (I had one bolt break on me while trying to twist a pin loose - they are tighter on that side, which makes me suspect the enginge runs a tad hotter on the driver's side on the 560.)
It's a real pain. And as Morris said (and as I've learned the hard way on an old VW Dasher back in the 70's) - always use no-seize compound when putting in bolts at locations that gave you trouble earlier....
1989 560 SEL (black/black)
2001 Audi TT Roadster (silver/grey)