Bigger injectors flow more fuel.
You only need to get bigger injectors if your current ones are maxxing out, but from the sounds of it, they won't be.
In a CA they will push about 200-220 rwkw in a tuned state, stock CA's have 370ccx4 (1480), RB20's have 270ccx6 (1620cc), so 444cc's in an rb20 would probably be enough to push the limits of the stock internals.
Smaller injectors are easier to tune for, when they get too big tuning becomes a bit harder (for idle etc).
Hope that helps.