Injector seals still leaking!

Okay, two of my fuel injectors were leaking externally so I figured I would just replace all the seals and everything would be fine. So I ordered the parts from the dealer ($100!) and installed them last week end. I figured that solved the problem. Low and behold, I smell that familiar fuel smell again and sure enough, the same two fuel injectors are leaking again!.. just not as badly. *** could be causing this? Is it possible that the housing of the injectors is cracked or something? I didn't see anything like that though. Also, how do I take off the injector plugs? I was no able to do that when I replaced the seals. Thanks for any help.