Is changing the fuel injectors(or at least the fuel injector nozzels) a do it yourself job? I wanted to check to see if they were okay by taking them out, but I wasn't sure if you could just take them out and put them right back in or if some adjusting was needed before reinstalling them. To save me some time, is there any way to test the function of them without dismantling anything?

On the 16V engine it's a fairly easy job. Of course new seals are needed.