The fuel injector is a vital part of the fuel system on today's multi-port fuel injection systems. With a stock factory production vehicle the engineers at the assembly plant have carefully calculated the correct size to make sure the car operates properly with a great amount of detail for driveability in town and on the highway. Once you start adding performance upgrades such as superchargers and camshafts your fuel requirement changes with the increase in horsepower. The first thing that you need to learn is that adding larger fuel injectors alone will not create extra horsepower. You will need to calculate the proper size injector for the size engine you have and the horsepower rating to find the actual fuel demand for the engine.
Injector Styles - Depending on your year, make and model there are typically three body styles of fuel injectors the EV1, EV6 and the EV14. Some fuel injectors are catagorized in length as well with two sizes available, the long (most common) and the medium length. There are also two different style connectors the Jetronic/Minitimer and the USCAR. Also depending on some manufacturers there were two different impedance levels a low and a high impedance. For example: Ford uses only the high impedance 11-12ohms or 11-18ohms units.
Connectors - If you vehicle has a wiring harness designed for a Jetronic style injector and you prefer a USCAR injector Ford Racing makes an adapter to make this work. If your vehicle has a wiring harness designed for a USCAR style injector and you want to run a Jetronic style injector they make an adapter for that as well.