waiting for the 
"sold out" sign on curent batches  

Almost pulled the trigger but saw they wanted $119 for shipping.  I hit the little red x.
yeah it comes to 814 .    if you have a psu that will work these are pretty good
if you do not have a psu the s-4's may be a better deal for you.
an s-4 comes to 930  . 
 I have a house full of s-3's and psu's.  the sp20 is a good upgrade for me.  
my goal is sell 6 s-3's   they use 2200 watts and 2 evga's  1300 g2  to hash  2760gh
I should be able to run 3 sp20's use 2280 watts and the same 2 evga's    to hash 4000gh  
I save :
1)room 
2)wires 
3)power  efficiency
plus   I get 1.2th more hash
with the sale of the 6 s-3's  my cost to upgrade is okay  say 3 x sp20's  = 2500 - 1200 for the  6 s-3's =  an outlay of 1300. 
If I mine the sp20's for 3 months I get back the 1300.   but i had the psu's on hand
You just want to play with new tech-totally understandable.
Otherwise, what prevents you from just keeping your 6 S3-you said that they already paid for themselves and they are very-very profitable (with zero cost and 10c/kw electricity), especially considering the heat. I calculated that if you include heat savings, each S3 uses just $20-21/mo and produces ~$55-61/mo right now.
That said, I am greatly salivating at Sp-20 just because I want something new, maybe will pull the trigger anyway.
I am thinking of putting Sp-20 possibly in upstairs attic that is not air conditioned.
Have anybody done this (Sp-20 at wildly fluctuating temperatures)?
well remember I had 12 s-3's moved 3 out down to 9 s-3's  moving 3 more out drops me to 6 s-3's.
and now the 3 sp20's .
     so I will have 9 pieces of gear not 12.
  my space and my power is limited.  I can  fit 12 s-3's
  Actually I can 15 s-3's in my garage and 2 in my friends office  in terms of space. 
 in terms of power I can run 12 s-3's in my garage and 2  s-3's in my friends office.  this would be realistic for the winter and doable. max of 6.5th
 having 4 sp20's   and 6 s-3's  max of 8.6th   
better yet 7 sp20's no s-3's  works better. 9.1th max  .
 my issue is power cost is high in NJ :
16 cents JUNE 1 to Sept 30  
10 cents OCT 1 to May 31--------------with the bonus heat savings factored in.
I get .55-.57  watts   with the sp20 underclocked  
The s-3's go down to .74 watts   maybe .68 with the pencil mod.  
     The extra efficiency means a lot.  So for me the change over from s-3 to sp20 makes sense.  I stay in the game longer and this gives me more time for the bull runs like  March-April 2013 or Oct- Nov 2013.
Those 4 months  made more for me then the other 25 months of mining I have done.