About 400 miles a tank under normal conditions, but when I go to fill up again I always have about 1.5 - 2 gallons left - so if I ran til the tank was empty I would get maybe 425 or so. If I'm driving aggressively for the whole tank, it drops to around 360. Only mod that might affect this is my V2 CAI, but my mileage went up a bit after I installed it.
Honestly I don't pay much attention to mileage, I just love driving my car so gas is a given expense in my book. Like eating or buying toilet paper.