Just quick flashback here. Looks like the kits still using 2 solenoids? One for NOS and other fuel enrichment with nozzle choices? If running forced induction a blow back through intake has no place for pressure relief so the weakest component will blow apart way before reaching air box. Also a bit different from what the dentist used to offer (no sulphur content). Nitrogen just keeps 02 from pre-ignition until temps are reached 500+ degrees F. Nitrogen will then burn off or release the pure O2 in cylinders if all’s well. Lots of extra fuel also needed for cooling engine so no pre-ignition with that.
Germany started using in aircraft (WWII), their doing and also water/meth injection gaining popularity those times. Merely passing forward info I found interesting 40 or so years ago- just sayin’…