If you want it done right where the injectors are cleaned and flow tested then remove them from the car and take it to someone with the equipment. Rich at Cruzin Performance will also do this for about $12 an injector. You mail them to him and he inspects - cleans - flow tests each one and gives you a detailed report.
I have used a combo of mineral spirits, Techron fuel injector cleaner, and Seafoam. You hook up an old fuel pump to your fuel rail off the car. Hook a switched (or pulsed) 12v source to one injector pin and a ground to the other pin. Let the cleaning fluid pump through the injector into a graduated cylinder to measure each injectors flow rate.
This is Dodgerunner's setup. I made something very similar using his idea.
