850km is my average. If I really try I can hit just over 900km. You have to work at it, skipping shifts, watching the fuel mileage meter, etc. I drive 160km a day mostly through country roads with few stops and 60km zones. I do not go above 100km/h. If I take the highway with 120km/h speeds I lose almost 100km from a tank. Cruise control easily adds 5%. Manual transmission is worth 10%. Don't believe me... look it up. When gas was $1.40 a litre and fill ups were $85 I learned to squeeze out what I could. I read about hypermiling on the net and went from there. Figure on $55 to fill up now. Be forwarned, push it hard and you can see 600km out of a tank. My wife only gets about 750km when she drives.
A few quick notes. Pre 2006 means it is an E46 chassis with a 2.5 litre motor. This is the same motor that is in the E90 323. Drive both an 05 and 06 325 and you will see and feel the difference. All E90 325's have Bi-xenon lights. You will appreciate leatherette in a daily driver as it always looks good. There are not too many manual transmissions for sale used. Less than 5% of all BMW's come to North America with a manual so you won't have a lot of choice. Most seem to be automatics with premium package. Good luck with your search and remember I know where this a nice one available