Personally, I think the choice of what engine to swap in comes down to your choices of what compromises you want to choose.

Like any project, there is no "best" way. Any project is nothing more than a selection of compromises. You need to decide what you want the car to be when done, then choose the compromises that get closest to your goal.

As my interest is autocross if I go beyond the current A15 project for power, I'm leaning towards the CA18DE. Handling is the most important measure to me followed by engine response. Turbo lag and adding weight to the front of the car are not compromises I'm interested in.

If you are more into straight line speed then the heavier engines may be what turns your crank.

Gary