If I switch from a 700R4 to a T56 out of a 1995 T/A (read as: not aftermarket) do I need the Spohn crossmember? I hope not considering I already bought one...

It makes life easier to use the spohn cross member and torque arm. You'll have to fabricate something otherwise.

So you bought a 700R4 Spohn crossmember? If that is the case, yes, you will need another crossmember of some sort. The 700R4 does not mount in the same spot as the T56 will. But Spohn isn't the only company that makes them. Skulte Performance Designs also makes a thirdgen T56 crossmember.

No I currently have a 700R4 in my car, but I am swapping a T56 in. I already bought a Spohn T56 crossmember but then someone said something that got me thinking that you may not need it. I would rather not modify things, so I am just going to keep it.

I understand that more than one company make this. However, I chose Spohn becuase I have purchased from him before. In addition, anything with his name seems to be a quality produced piece and people never have anything but good things to say about him and his work.