05 GTO...LS2...A4 Transmission. Totally stock I got 23 on highway and 18 in town.

Added 3000 stall...now 21 highway...16.5 in town.

 

my 04 M6 the best i have averaged is 28.6 and that was at 65 mph cruise no stops. my buddy had an 04 A4 and he drove to houston just about every weekend in it and got around 20-21 at a 65 mph cruise. A4 Gear ratios 1st Gear Ratio
3.059:1

2nd Gear Ratio
1.625:1

3rd Gear Ratio
1.000:1

4th Gear Ratio
0.696:1

M6 gear ratios
FIRST
2.97

SECOND
2.07

THIRD
1.43

FOURTH
1.00

FIFTH
0.84

SIXTH
0.57

 

i have headers and exhaust, and i get 17 city, or mid 15s city if i beat it up. i get low 20s highway.