The reason I didn't upgrade was simply a time issue. I have pretty good flexibility to work from home but I take my son to daycare near my work and I really can't work from home while he is there, or rather I can, but I'm not supposed to and I am really against just popping him in front of the tv for 6+ hours. Any way, I didn't order the killer b initially because I was hoping I could get one I could put in over the weekend and save myself the labor. All that's in this thread somewhere, but once I found out on Monday I could get the work done then and they had a part I went for it.
Sorry, I don't recall where I saw that there was a new part number and the locations were instructed to replace the part with the new one. If I get nervy about it in the future I'll swap it out then.