no replacement for displacement????

yes....air to water kits like Frozenboost has.

I advocate Water Injection, because of the simplicity, the Lowes/Home Depot "repair" parts...and the effectiveness.

I also advocate (WI) because it does not hinder engine compartment/glovebox/inner fender/mounting.....a simple 1 or 2 gallon water tank somewhere....a electric RV water pump, feedline, a nozzle...a hobbs switch for the pump Power....your in business.