thought id add my figures, 2008 sr5 D4D
just added Front mount intercooler,
have had steinbauer on max setting and 3 inch exhaust all the way ( cat and one Muffler) & wrapped in ex wrap
egr block with 7 mm hole , k and n air filter, running 32 inch tyre (265 70 17 coopers) winch and toyota breaker steel bull bar and tow bar.
and too much crap in tray (eg steel draws, hi lift jack 80 liter water tank ,fridge 50 lt , various camping essentials and tools galore, never bother to remove anything im to lazy,and finally long range tank,
and im really to happy to report i average 10.6 l per 100 ks
i do more city driving than country. not happy about that thou