The 1TB option was reduced to $600 ($540 on edu site) when buying a nMP,
and the 1TB ssd now has 50% faster upgraded read/write speeds then when the nMP was first released (in early 2014 if we're being honest here Apple) - 1GB/s vs 1.5GB/s
The D300 cards are super gimp/junk, D700s make a huge difference.
There's also the Apple education store which is roughly a 10% discount.
Or the refurb store for 15% off, but they rarely (if ever) offer D700s with quad-cores.
Unless you want to move to Windows,
Sell your nMP(some cases they sell more on ebay then new) and buy a 4-core 12GB 1TB D700 model...
...then upgrade the CPU and RAM yourself!
You'll need to replace the crap thermal paste Apple uses to "Solve the nMP Cooling Problem" on the CPU and GPUs.
No point to pay
Tax for a better CPU since you'll need to access the CPU socket anyway to apply Arctic Silver.
And $3500 + Tax for a 3 year old CPU? No Thanks Apple.
The Xeon E5 2697 v2 12-core is a beast of a CPU though
Double the ring buses, memory controllers, and cache then the 4, 6, and 8 core options!
When properly cooled, aka thermal paste "upgraded", it runs all 12 cores at 3Ghz and up to 6 cores at 3.5Ghz
OWC has a great easy-to-follow nMP CPU upgrade how-to video:
Thats what I did.
I managed on eBay to get a more recent serial pristine 2nd-hand 12-core E52697 v2 + new Apple OEM 32GB (4x8GB) ECC "black" RAM for $1,050.
If going 2nd hand be wary of ES/QS versions of Intel E5 v2 Xeons; however,
A colleague claims he got a 12-core 2.4GHz QS sample on ebay for $300 and it runs great in his nMP.