[m2cWW]

Hey guys! I'm in the process of turning my M2 Comp into a track car. It seems like a water only injection system might be a lightweight, easy mod to gain a solid dozen horses and radically drop temps. Having researched it a bit, I'm only running into one issue. It seems to be a massively complicated field.
That being said, for water injection only, how much will tuning for the WI matter or can we just slap it on the existing tune and call it a day? Moreover, how complicated a system will I need to use? I was looking at aquamist and there are 4 different tiers of complexity in the controller that I cannot for the life of me differentiate. Any help would be vastly appreciated.
Last thing- as regards failsafes. On our cars, which sensors is it best for the failsafe to be triggering from?

Car details:
2020 M2 competition, FBO with 1/8" meth bungs available on charge pipe. Straight pipe, manual gearbox. Plenty of other mods irrelevant to the topic. Probably at 510 horse because of crappy CA gas. Not doing e85 because I live in SoCal (no corn around me). Considering meth, seems to be highly illegal though. If I am wrong about that PLEASE tell me. Cheers guys!