unfortunately our celicas can't use a dry nitrous system.. although.. its still ok to buy the dry kit because all you need is a fuel solenoid and lines/fittings to make it a wet kit.. oh yah and another fogger. but i think you can get a wet kit for around the same price as 550 or even cheaper.
btw try
http://www.importcarpartsplus.com/ they have pretty good deals on nx