I would not take a hammer to the injectors; that is just asking for trouble. Have you tried tightening down the fuel rails some to make sure the injectors are all seated properly? I can't remember if my Dorman Intake had coned shaped interfaces or not, but I'm sure they did. I'm sure someone else more experienced than me will chime in, but it seems like if you had an issue at the injectors not seating properly, then you would have a fuel leak there. If you don't have any fuel exiting out near this area, then I would say you don't have a problem there (other than maybe a bad injector).
How many miles are on the car? Have you changed the PCV valve? If not, I think this can cause idle problems as well. If you have a friend with a 'Stang, see if you can borrow someone's IAC Valve to see if that is the problem.