When driving on the continent last week, I tested the top-speed of my A4 Avant 3.0. It maxed out at 145mph (prob had another 1-2 mph) before I got the willies and slowed down. This compares with the manufacturers spec of 151mph. Obviously max speed depends on various things such as wind, weather etc. but it got me wondering whether the A4 will go fastest in 6th or 5th (I was in 6th). I know of a number of cars that won't do their max speed in top because the revs are below the level at which they deliver maximum power. At 145mph my engine was doing about 5.5k rpm, whilst max power comes at about 6.2k. Would it go faster in 5th?