Chrysler Repair: 2001 Town & Country PCU Problem, pcm, alarm system

Question
My 2001 T & C started running very poorly.  I took it to a dealer and they ran the diagnostic and determined that two cylinders were not getting fire and that the PCU was to blaim.  The want $700 for the part + 2 hours labor to install and program?.  My question is, could a PCU from a used vehicle of the same year and engine be installed without going through the dealer?  I'm ready to get another vehicle and I really don't want to invest $1,000 if I can keep from it.

Thanks in advance.

Josh

Answer
how many miles are on your van first of all. Second u would take a chance if u install a used PCM and dont know what was in the van u are taking it off has  like an alarm system. If the old one does have an alarm and yours does not  and u plug that used one in  well u just told the other computers that u have an alarm and the PCM will be requesting from the other computers are we ok to start up and they will say no because they dont see the sensors and such required by an alarm system. And thats just one issue that could happen. I have a few more but I hope u get my drift.