Al hamd o lillah I got my second SUV i.e. 99 surf with 1KZ-TE intercooler and she is doing very well.
8 km/l in city and 11 km/l on motorway @ 110 km/h.
One of the reason could be that it has done only 100000 kms original meter reading, reconfirmed via changing its original timing belt, which is still in good condition.
Need to change its oils though.
So if you find a decent SUV with original 1KZ-TE you will love it, regarding KZJ78 its shape is not aerodynamics and at high speeds it will suffer with too much air resistance and secondly surf has part time 4wd, means good mileage.