get it from any nx retailer,if money is a problem,you can pick a used kit up from ebay.
as for installation,if you have installed a car stereo system before,and can understand instructions and good with tools you can do it on a celica.
the hardest thing,being the wiring to open the solenoids,and cutting the fuel hose in the right location and squeezing in the t fitting into the line.
do a search,or i'm pretty sure one of the members would point you in the right direction.