[Biturbos4] Headlight lamp replacement

[Mark Isenberger]

My 2001.5 S4 just came off warranty and the left headlight lamp has burned 
out.  Is the replacement simple?  I'm hoping to avoid going back the the 
dealer for this (they've butchered something on almost every trip there).

Is the procedure documented some where?  Do I need to disconnect the battery 
when replacing the lamp?  If so, will the loss of electricity cause errors 
or other losses of memory?

Thanks for your help.
Mark