I see, now it makes sense that it passed, I didn't know if things were old enough our state stopped inspecting them. I'm sure the O2 sensors, higher compression, ECU will help get it more efficient. For towing as heavy a load as you will be an ecoboost or similar engine is the right tool for power and efficency. But it doesn't come in a vehicle you want. Maybe when this car is through it might look better, but don't check it out on our account. water injection acts like an octane boost, allowing you to run a leaner mixture in those cases without knock. You want to have it under control to inject at those high throttle or high rpm situations when you might knock. If the car doesn't need higher octane on the tune you have, then no need for the injectors. You mix the water with methanol so it doesn't corrode. I would not expect it to help much on your engine.