Id say the con is being expensive. Lot of money for a cold intake charge. youre gonna use up your nitrous a lot faster than normal. If you didnt care about being fancy... you could just crack a nitrous bottle open and spray your intercooler with it before you run. All theyre trying to accomplish with those systems is a cold intake charge.

You can also route your windshield sprayer to your intercooler, obviously water isnt going to have as great of an effect as nitrous for cooling, but its the same concept. Cooler air = more hp.

Something to do if you have some old nitrous parts laying around going to waste, i dont think id buy one of those purpose built kits for it.