SR20DET is a fine choice, many have successfully swapped into Datsun 1200
The lower control arms are perfectly fine for the power of the SR20DET -- no need to change them.
* To handle the extra weight of the engine, fit stiffer springs
* If you want to adjust camber, you can move the top mount or install camber tops. See
CamberThe purpose of brakes is to stop the car:
* If you plan on driving faster speeds, it's a good idea to improve the brakes
* If your government requires brake upgrade when engine swapping, then upgrade the brakes
* If you plan on exceeding the vehicle weight capacity, then upgrade the brakes. SR20DET adds about 150kg to the car, which is still within specs (like carrying one or two passengers). But to carry four passengers + the extra weight it would be a good idea to upgrade the brakes
* If you value increased safety in general, then upgrade the brakes -- even if you have a stock A12
Luigi from Portugal is swapping S13 Japan brakes into his 1200. I suggest swapping the S13 EUROPE brakes, which are larger and more common but require 14" or larger wheels
If you want to use 13" wheels, I suggest swapping the Datsun B310 245mm brakes (1200 brakes are 212 mm, so this is a substantial upgrade)