I had disco 300tdi before the fronty and sold it for the fronty. They are very thirsty as they are permanant 4x4, think an average was 22 to 25mpg and got bored of it within weeks unlike the fronty which is a better drive, more economical and even after 12 months I still enjoy driving it.
The hilux surfs suffer from head problems I had friends who had them.
The fourtrack would be a choice I would consider. Very capable off road return a reasonable mpg and not badto drive, down fall is parts can be pricey
The trooper much like the fronty. I would describe the drive as a cross between the fronty and disco.
My suggestion stick with a fronty
Regards Ady
Pics of the motor can be found
hereComment on the motor
here