Day 3 of the 335i, I had a full tank of petrol when I had it Wednesday, i've done about 110miles in it, that's a mixture of town and M4 driving, with a mixture of sensible driving (6th gear and light throttle touches) and occasional booting it (the speed and noise is addictive).
Looked down at the fuel gauge as I got into work, its used just under a quarter of a tank, which for what i've been using it for is pretty good going for a car that weighs a bit and with 300bhp, I've worked out about 31-33mpg.
I know you really shouldn't be even be thinking about fuel consumption with a car like this but I thought that's really good, and its a 56 plate car aswell.
yeah that's what I used to get - though usually slightly less (28-29mpg) though that was with town and back roads rather than motorways.