CPU question

["Ronin Hyde" <ronin@inna.shove.your.spam.up.your.net>]

   After looking at two IIGS motherboards, I noticed one was rev A and the
other is a rev D. Only other things I could notice was faster memory (12ns
instead of 15) and a G65SC816P-3 in the A and one with a -4 in the D.
   Since I'm going to try to snag some other GS's for parts and try creating
a Frankensystem. Are there any pages on hardware modifications that can be
done to the motherboard (socketing chips, faster memory, etc) or has anyone
tinkered with it?
   Thanks for the time.