Wow, there's a TON of mis-information going on in here.

Mostly find the "Nitrous Express is the worst kit to have" statement one of the dumbest things I've heard.

Direct port isn't the safest. Its alittle more dangerous than all the kits mostly because they require more fuel to be mixed in with the nitrous and without major upgrading you can easily have yourself a blown mani or worst a blown motor. Direct port systems are mostly used on 4cyl engines for spraying bigger numbers and because its "safer" to spray those big numbers straight into the intake runners than through the one intake tube and through the TB. If everything is upgraded accordingly and you don't get crazy with the jetting this does become the safest kit.

Nitrous EXpress, NOS, Edlebrock, Nitrous Works, etc etc are all your standard car nut nitrous kits. NX and Edlebrock have been known to sell the highest quality solenoids present day since say, 02-03. NOS has always been a leader until then.

Zex is mainly for your beginners who want everything as easy and ergonomic as possible. Don't get me wrong Zex now does have systems that get pretty complex but they grew on making a simple easy to install kit for your everyday customer.

No kit hits harder than another kit. That's all based upon bottle pressure, solenoid flow size, and jetting. NOTHING else.

Wet kits are liked more than other kits because once you "T" off the fuel line you don't have to worry about anything else fuel wise (smaller shots) besides having adequate fuel pressure through that line.

Dry kits, you usually have to clean your entire fuel system or upgrade fuel pumps and injectors to make sure everything will work correctly. Most people blow motors from the nitrous kit leaning out over not enough fuel being delivered to a disfunctional "stock" pump or clogged injectors.

Easiest ways to tune a nitrous system would be to know your fuel pressure and to make sure it stays in optimal range, Wideband a/f gauge, and whatever equipment you would like to use to pull 1-2 degrees of timing while spraying. 50shot pulling timing isn't neccesary but 75-100+ it is crucial. I'm not up to date on what evices are out for imports such as honda's to make that whole process easier but this K-pro thing is sounding pretty good. I myself use a MSD DIS-2 Programmable which takes timing as the nitrous goes in.