The thing about the FX53 is that it has unlocked multipliers. That will definately help on your overclocking achievements. :wink:
The FX-53 is an old 130nm core, it lacks enough headroom (compared to a 90nm San Diego) to actually make use of the unlocked multipliers, not worth it IMHO.
The 144 is the lowest end S939 Opty, only worth it if you are going to OC as the extra cache doesn't outweight the 200MHz gap between it and your 3200+
It would be a good idea to tell us how much you are going to get those CPUs for, "almost for free" sounds too good to be true, there might be a catch.