I am looking at a BF XR8 ute with the ZF 6 spd auto in it.

I do mostly highway miles with about 35% city stuff. I don't drive too hard but sting it up every once in a while.

Now, what sort of mileage/fuel useage would you expect to get out of one of these?? I understand they can be a little bit heavy on juice.

Also, it has a hard cover with a small spoiler on it if that makes any difference to mileage on the highway.

And what sort of difference will I notice between that and a similarly spec'd XR6T when it comes to fuel??

My old 302 Super Pursuit got around 15L/100 around town and it did about 10L/100 on the highway.
I did tend to get up it a bit around town too
In comparison my 4spd BA Pursuit sits on 16.2 around town but was up around 17 before I put underdrives and cold air on it.
XR8's maybe a little worse due to the lower compression? but underdrives etc will obviously improve that.
Our BA 4spd turbo sat on around 14.7 around town and got down to 9.8L/100 highway.
A 6spd should be a better still.

my bf 6sp auto was getting bout 10l/100km(hwy) with mods, xforce headers, twin 2.5 straight through zorst and k&n filter now i have bullbar (4inch 5 poster) it gets 10.5l/100km