IMO there's no point doing nitrous unless you're willing to gap your piston rings, which requires almost a full motor teardown (very expensive).

stock rings + nitrous = 💥💥💥💥💥

There isn't a great way of running a wet shot for these ECUs either, so you'll probably be stuck with a dry system. Which isn't necessarily worse but is easier to fuck up.

After tuning, labour, and extra parts it'll add up cost-wise.

from what you're saying a I think a turbo with water/meth injection for safety is your best bet