Gas mileage is reaching pink sock levels.
#12
You'll need an IC from a '92 S4 or a rest of the world C4 S4 or S6... and even then
it may not be possible if the wiring is not present to hook it up. I have never heard of anyone adding one after the fact.
#20
Your car in the fuel line recall?
I smelled gas 2 yrs ago and took car in for the fuel line recall. Can't remember that it affected mileage much. BTW, I get at least 360/tank (22mpg+) on my 93 S4 - 249K miles.