I have a gtx 970 sc acx 2.0.  It is a good card that has an asics of 84 or so and overclocks to 1550/8000 at the very max but it is not absolutely stable in all games (I run 1510/7900),  it seems that voltage jumps will crash it with power usage jumping to 140 then crash.  This is just my current situation below are my issues.
 
Now I have submitted for the new gtx970 ssc (3975-KR) using the step-up program.  The questions I would like to have answered are.
 
1.  Is there any difference between the new gtx970 ssc (3975-KR) and the ftw+ other than a backplate and a another 25MHz.
 
2.  Will the backplate on my current gtx 970 sc fit onto the stepped-up to gtx970 ssc (3975-KR).  I noticed that the new card is 15.2mm longer.  It would seem that somebody could compare the screw holes from the old models to the new models,  there is only one size fits all backplate now I believe. 
 
3.  when is the release date for the FTW+.  This way I can decide if I want to change my step-up to the ftw+
 
4.  will the ftw+ be offered on the step-up program, the new gtx970 ssc (3975-KR) is offered in the US as I have submitted for one (It is also for sale unlike the FTW+).

Those are already pretty high clocks. It seems unlikely and we haven't seen much in the way of general overclocking results for these new 970s, but if your unlucky you might not be able to reach that high with a new SSC/FTW+. My FTW with an ASIC of 68.4% will only do 1455/7450 with a BIOS increasing TDP limit and increasing voltage to 1.225. At this point I believe it is unknown as to whether or not there is any difference between the SSC and the FTW+ other than what you've already stated. The release date for the FTW+ is also unknown, but hopefully this will be soon. Considering the SSC is a step-up option I think there is a good chance that when the FTW+ does release it will be as well. As for the backplate, that's a good question that someone from EVGA would probably have to answer. I didn't know the SSC was longer, just ordered a backplate from Amazon and would like to know the answer to this too.

You're probably right about the overclocking potential of these cards fkrlll. I know I can't get my FTW to use more than 210 watts because of limits placed on the gpu I presume. Not sure about EVGAs other 970s, excluding the SSC. I'm curious as to what the factory TDP limit actually is on that.

staypuft

fkrIII
2.  Will the backplate on my current gtx 970 sc fit onto the stepped-up to gtx970 ssc (3975-KR).  I noticed that the new card is 15.2mm longer.  It would seem that somebody could compare the screw holes from the old models to the new models,  there is only one size fits all backplate now I believe. 

Most likely won't fit, check out the pictures on newegg.  The GPU has been shifted towards the rear of card, amongst numerous other changes.
 
 

Doing a step-up to from my two SC's to the new SSC just like fkrIII is. I am hoping they do fit as I really do not want to buy backplates for my new cards. :(

fkrIII
well my step up got to step two now they just have to review my receipt then the new card will be on the way.
 
I have 12 days left for my step up program to end.  I suspect another email in a day or two then I have 7 days to give payment so if they are going to release the ftw+ they need to do it soon for me to change my step up to the ftw+.
 
you can change your step up to a different card right up to the time you either give them payment or you run out of time.

Very nice. I hope they release the FTW+ soon. I've only got until the end of the month for step up, but would be okay with going from my FTW to the SSC if the FTW+ doesn't come out in time and if it's allowed

fkrIII
well the ftw+ is out at ces and it looks to be the same card as the ssc except it has a higher base/boost clock and also a backplate.

are the voltage and cooler the same too?

The answer to #2 is no.  The old backplate does not fit on the 3975-KR (the new SSC).  This was frustrating to discover.  Also was bummed to learn pick your path expired last week… Just before the FTW+ came out.  /sigh
 
(around 5 mins in for proof )