Replace 4Zz With A 1Zz

[SwithiN]

Hey There,

So I have a e120 with 4zz that is fairly tired. I would like to put a 1zz in, mostly because I can get a good condition motor with all the bits on for fantastic price and driving a 1400 is making me wanna tare my eyes from their sockets.

SO the question... how big a job will this be?

1) Do i need to change transmission?

2) Will the ECU learn enough to run the engine ok?

3) Are there any serious sensor issues with this kind of a swap?

I have looked everywhere I could find and i looks like there is not a whole lot to it. But would really appreciate any input.