hehehehe...what happened to direct port?
...yeah, but wet kita are safer...with a dry kit you run the chance of running extrememly lean, and blowing your stuff all to hell...also, with a wet kit, each cylinder has its own nitrous injector, so the juice is distributed more evenly, whereas a dry kit has a single nitrous injector in the Intake tube. Wet kits are better because the nitrous and fuel is mixed BEFORE it reaches the cylinder, and a wet kit makes the nitrous mix in the cylinder for combustion with the fuel...wet kits are way safer...
With BOTH a wet AND dry kit you run the chance of running lean and having detonation occur IF you do not adequately prepare for nitrous. You can run lean if your bottle pressure is too high because of the ambient temperature on a very hot day (use ice to cool it). Detonation is the uncontrolled burning of the air/fuel mixture in your engine which can damage vital components. Detonation can be caused by a variety of factors being met which contribute to too high pressure and temperature in the combustion chambers:
Running too lean can cause detonation. You can have detonation if your spark plugs aren't cold enough or you haven't retarded your timing enough for the shot you are using (get a timing retard computer if you want a big shot like 75). You can have detonation if the octane of your fuel is not high enough. Octane level is defined as a measure of a fuel's resistance to detonation (the higher the better).
As I stated earlier a dry kit cannot be used b/c the celica does not have a fuel return line, which causes another problem called fuel puddling, which also leads to explosive results.
In conclusion, no need to be worried: Just use a wet kit AND adequately prepare for nitrous...extremely important.
More comments on AZZKIKR's post:
It is not true that with any wet kit each cylinder has its own nitrous injector. That is direct port which is a kind of wet system, a subset of wet.
When talking about a "wet" kit, a single fogger nozzle is implied. Single fogger wet sprays fuel and nitrous in the Intake
tube from one jet, positioned after the MAF sensor but at least 6 in. before the throttle body, to be precise.