the current engine (3rz) is quite slow so i am thinking on swapping it with a 1UZ cuz it has got plenty of power, I just want to know that if it is a good idea to do it, and if it is then what are the most common problems I could encounter while swapping it?. Plus what do you reckon the fuel economy would be? the 6-7 kmpl fuel average was for the lexus lc200, which is much heavier than my own truck, like 1 ton more. So i was wondering if the fuel average would be better in my own truck or if it would be the same?