These DEA and FBI are not 2181 positions. They are 1811, which means that you are required to be a Special Agent first, pilot second. DEA requires that you spend a minimum on the street investigation drug cases before you are considered. Their main base was in Dallas, not sure now. FBI requires that you be an agent first, pilot second. They have recently revised the policy of having a pilot in every field office to only the biggest. Most of the FBI flying is in C-182's, unless you graduate to the more elite detail in DC, tough. No extra pay for FBI pilots, extra 25%for DEA.
Customs pilots are also Special Agents, but only fly. They recently completed their hiring off the advertisement from Jan '04. Not easy to get on either. All of these required a college degree and enter on duty before age 37. With the FBI if you are a white male with a bachelor's degree, forget it. Won't hire you without a master's and a lot of pizazz.
Customs, DEA and FBI all fly single engine planes, with all of them having exceptions for jets and helicopters. I mean they have them, but not easy to get there.
Good luck