Also on that note, i picked up an e36 m3 and i'm getting the same mileage as 318s,325s,323s,328s.
averaging 600km+ on 52L (i fill up early) probably closer to 700+ if i ran it to empty.
worst was 500km on ~52L when i was enjoying the s52 every chance i got.
And this is mostly city driving. Haven't done lots of long hwy driving yet.
I'm enjoying the power and the better fuel economy over my old e30.
Only downside is i now use premium, but im more than okay with that.