I had a 91 SR5 with a 22r. I ripped that out and stuck in the 3VZ-FE 3.0 litre V6. It was pretty straight forward because I could buy parts from a V6 4runner and parts (like radiator, air cleaner, ECU, clutch cylinder etc) all bolt straight up to existing holes. This made the job look ex factory which helped at inspection time. With a set of extractors and T/B size increase the thing went pretty well.