Confused as to which VAG product I need for 2004 S4 Avant....
 

Kll USB or Hex-USB+Can or what?

whats the difference, whats needed?

The KII-USB will work fine, The major difference ...
 

is that the HEX+CAN is designed to cover all model years from 1990-2009 and it has the extra hardware to cover the cars who have diagnostics on the CAN bus.

The HEX+CAN style interface, with more electronics in the interface, may sample live data a little faster than the KEY style interfaces.

The KII-USB will work for models from 1995 thru roughly 2005.

For more complete info, take a look at our VCDS World Compatibility Charts.<ul><li><a href="http://www.ross-tech.net/VCDS/download/VCDSCompatibilityCharts.pdf">http://www.ross-tech.net/VCDS/download/VCDSCompatibilityCharts.pdf</a></li></ul>

thanks!
 

So if I just want to use it on my US, 2004 B6, S4 the KII-USB is fine, correct?

It seems that someone was commenting on CAN bus as early as 2000 S4,

Yes - on the '04 B6 S4 KII-USB is fine
 

There may be modules that talk to each other via CAN in your car but the diagnostics are not presented to the DLC port via CAN. The B7 A4/S4 was the first to have any diagnostics on CAN. I know, I drove a B7/A4 for 3 years.

thanks again!