Please Explain Audi Nomenclature

[Tom Lazay <tlazay@ultranet.com>]

Hello,

I now own my second Audi (A4Q) and I have been following the list for 6
months now. There are still a few things I still don't understand. Could
someone explain the meaning of the following terms and/or Audi specific
features?

-S  as in 5000s.
-CS as in 5000cs.
-UR as in UrQ.
-VDO.
-TDI (I saw one in Paris I think)
-What is the difference between a 100 and a 200.
-Can you get an S6 (New) in the US now? I didn't see it mentioned in the 96
or 97 brochures.
-What is that funny little air dam on the drivers side wiper that seems to
sprinkle wash fluid back onto the windshield after the wipers clean the
glass. Why is it only on one side?
-Have Audi's always had the red dash illumination (I love it).
-What ever happend to the 80 series?

Is this evolution correct?...
4000 -> 90 -> A4
5000 -> 100/200 -> S6/A6
V8 -> A8

That's all for now. Thanks in advance

-Tom
'97 A4Q