Consider getting a kit that offers a real failsafe. For example, the system should have some way to monitor that the system is actually injecting and is not clogged. If you have an electronic boost controller the failsafe should be able to disable it if there is no flow...and bring you down to wastegate pressure. If there is flow it will enable your boost controller and let you boost as much as you have it set for.
If you have a manual boost controller, the failsafe should have a 3 way valve that can disable your manual boost controller when there is no flow, enable it when you have flow.
Its the only sure fire way to make sure you only boost high when you are injecting. It make certain you dont have a clog, you are not out of water and you dont have a hardware failure.
This is an important part of any water injection kit which is why we made it an option, there are several kit makers that have this ability.
David