I don't know much about Nos but what is the Diff between wet and dry shots? mmm???

 

A "Dry" shot is simply just injecting the N2O. It relies on your factory fuel system (specifically the ability of the MAS and ECU to compensate)to supply the xtra fuel. This method is only recommended for Naturally Aspirated cars (unless you are running full engine management).

A 'Wet" system also has a nozzle for you to inject extra fuel at the same time. This is a much safer system, and helps avoid running lean on a factory fuel system. It is best for Turbo and supercharged cars where fuel is already being used in large amounts.

Both systems are still dependant on the abilities of your fuel pump to provide the fuel necessary.

With full engine management, either system would be about the same, as you can tune it perfectly.

 

isnt dry safer?

 

A dry system would never be safer just from the simple fact it is much safer to run rich (too much fuel) than lean (to little). Running rich may result in puffing black smoke out the back and terrible stumbling (and kill the O2 sensor), but its better than running lean which can destroy the engine.
The difference is only important for the street user, and I would always recommend a "wet" system. If you buy a dry system you should also have an A/F meter, an EGT gauge, and have a darn good clue about what you are doing.