Lincoln Diesel Specialties or Dan's Diesel if you want to send them off. I'm pretty sure one of the local to me heavy duty truck shops has a nice fuel shop where they do pumps and injectors.
I think to test my injectors was 50 a piece through LDS. Then they replaced the nozzles, flow tested, balanced, and sent them back with a detailed flow sheet. I think everything cost me like 1700 maybe? 400 for testing, 1000 for 45% SAC nozzles, 210 for one new injector body, and a little bit for assembly labor. Not bad. My stuff was gone for less than a week. I think they got them on a Monday and I got them back Friday or Saturday.
Btw...what injectors are we talking about?