[johnny_quattro]

Here's my rewording of the Waterloo post, to make it less USA/Canada-centric:

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Transmission Coding for 1997 to 1999 A8's
2000 and later A8's have additional codes explained below.

97 without Tiptronic
Code 00001 (set when leaving the factory) - Rest of World
Code 00002 (set when leaving the factory) - (for USA/Canada)
Code 00011 (DSP shut-off rest of the world). This coding makes the car more of a "European touring machine". It really makes a huge difference in the way the engine and transmission responds.
Code 00012 (DSP shut-off USA/Canada)

The following are characteristics of the 00011 code:

Holds 1st gear in tiptronic, upshifts to 2nd when it hits redline or when the driver shifts
Can downshift to 1st, as long as it doesn't mean hitting rev limiter
Shifts to higher gear in tiptronic when redline is reached
Shifting appears to be slightly faster in tiptronic mode
Adaptive shift pattern works very well, shifts to more sporty mode after a short while of inspired driving and vice versa
Kicks down in tiptronic in certain situations when the gas pedal is floored
Downshifts to hold speed downhill when using cruise control

00 and later with Tiptronic
The 00's and later have different options than the 99's and earlier. They can be coded as followed:

Code 00001/00002, stock coding
Code 00011/00012, sport coding
Code 00021/00022, stock coding, but will hold first gear in Tiptronic to redline regardless of throttle position and then shift to second.
Code 00031/00032, sport coding and will hold first gear in Tiptronic to redline regardless of throttle position and then shift to second.

2002 A8L (USA car)
Code 00002, stock coding
Code 00032, owner recode
Code 01002, after Audi serviced the car
Code 01032, owner recode after Audi service - The car holds 1st gear to redline and shifts to second.
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From what I can make out so far, the digits seem to signify the following:

1st digit, no idea, unused?
2nd digit, set by Audi engineer/garage
3rd digit, S8?
4th digit, does the magic!
5th digit, area/region (1 - everywhere else, 2 - USA/Canada only)

Please feel free to correct me if there are mistakes/anomalies - I'm no expert.