Nitrous is a stand alone system and has nothing to do with anything thats done to your car. A wet kit sprayes N2O and Fuel, you adjust the jetting to obtain the desired AFR. There’s a way to pull timing on LS engines without having the car tuned. Some sort of relay/resistor box or something, I don’t know off the top of my head. Buy colder spark plugs and run at least 100 octane on the spray for good measures!