The scene where Nolte attacks the three FBI agents is one of my favorite movie fights of all time. It's hard to call any movie fight realistic, but it gets fairly close and shows you just how powerful the element of surprise can be in a fight.
Being a retired Federal Agent of the Immigration and Naturalization Service, I also enjoyed that part. The FBI is infamous for taking the credit for all the work done by other law enforcement agencies. I believe their saying is, "The FBI and "other" agencies". Of course, now the FBI is the enforcement arm (strong arm) of the Bush administration. Notice how in the movie, the FBI was trying to pressure the LAPD to quash the investigation. They got what they deserved.