In late 1999 model year vehicles, produced after April of 1999, FORD switched to a returnless fuel system. The only way of knowing for sure is to look at your fuel system under the hood. If there is one and only one fuel line leading to your fuel rail, you have a returnless system. If you have two fuel lines leading to the fuel rail, you have a return type fuel system. The return type also has the Fuel Pressure Regulator directly under the TB, where as the FPR in a returnless system is reported to be in the fuel tank.
If you have a return type fuel system, there is no better kit than the ZEX kit. It is adjustable from 55-65-75hp and is all full proof. Only thing that the kit doesn't have is a RPM cutoff switch that will kill the power if a certain RPM is reached. Otherwise, it is completely up to the operator NOT to run the nitrous up to the rev limiter. You stop paying attention, and BOOM! limiter hits and the car runs lean for just the slightest amount of time and you will fry something for sure.
Just from my experience, if you are asking this many question, you shouldn't have nitrous on your car. Read everything you can about the subject and don't install a system until you understand all the consiquences of doing so.
