I'm pretty fine with all those crazy deals for a K3. If you have a relatively new camera (say K5 and above), K3 is not so great deal considering:
a) it's a good lens you didn't buy (say, second hand FA77)
b) it might require a new PC
c) or significant upgrade to existing one (memory/CPU)
d) and significant increase in storage space required
e) or at least significant performance loss in Lightroom
f) finally if you don't shoot much action (so AF is not so important) the IQ increase over 16mp sensor might not really matter to you
So, I tried. Now you can go and buy it.