I fill up once a week but I never let it get to the empty line in my ts v6... But I'd estimate I get about 500ks a week before I need a fill.

I have a chipped ecu that's supposed to increase power and fuel consumption... I dunno if it actually does anything in the consumption way of things cause I have it set for max power but it makes me want to plant my foot more so I'd probably get 600ks plus if I tried