Mine's a manual running on Goodyear MTR's with a 2 inch lift, steel bullbar, winch and snorkel with intake modification and a DPChip. I could give you some comparison figures.
BUT!!!, there is something to consider when you put slightly larger tyres on from standard and then try to do a consumption comparison. The circumference of the tyre is greater so there is an error in the speedo/odometer compared to standard. I run 265/45/R16 MTR's and now when compared to a GPS unit my speedo/odometer is spot on. So I should reduce the consumption by 3.3% to compare it to the original Goodyear Grandyucks.
So here are some figures that I've got in a spreadsheet and averaged out over time of general driving.
Tyre-------Size----------Consumption-----Corrected
BFG AT---265/75/R16--12.8 L/100km---12.4 L/100km
MTR------265/75/R16---13.6 L/100km---13.1 L/100km
Highway long distance driving has seen the BFG's as low as 11.6 L/100km corrected and on the MTR's 12.7 L/100km corrected. I don't have any figures for the original tyres but I think they are around 11.2L/100km from things I've read over the years. So the extra mods and lumpier tyres do make a difference.
Regards
D.T.