[Elecraft] K2 SN 192 ?

[H. M. Motley Jr.]

I have a chance to buy a rather early K2 in unbuilt kit form. It's serial number 192. It has the SSB adaptor, Noise blanker, Audio filter, a set of pre-wound toroids and the Revision B boards and parts and updated manual.  In doing some research on the WWW, I see there have been a number of changes/modifications over the years by the factory and others. I've run across alternate wiring for the AF gain and mention of a cure for BFO drift.  Does someone have a list of the various changes that I should incorporate while building this rather early K2 should I decide to take the plunge and buy it? 

Thanks & 73,
Puck