Dem, when I'm using my GT just for station runs and nothing else (short journeys, no chance to warm up properly) I still get over 400 miles from a tank. Best I've seen is 600 as well...think Matt & I might drive them in a similar way! My E30 2.8 is almost complete - dreading to think about the MPG I will get from that, haven't driven a petrol car for ages!