Hi,
Yes, I've been using the stc6 body for a few weeks now. It is my new favorite body. I have compared it with my mazdaspeed 6 body and mazda 6 GX body on medium/high grip carpet on Sweep QTS32 tires. I find it to fit somewhere between both mazda bodies. It is less lazy on turn-in compared to the ms6 body but is much less edgy and easier to drive than the gx. On lower grip surfaces, I might go for the gx body, but if traction is medium, I'd go for the stc6. On high traction surfaces, I found myself traction rolling more with the gx, and I also made more mistakes with the gx due to it turning in too fast and also breaking away more suddenly. Since you are on sticky sorex 28's, I think you'll be happy with the stc6.
Oh, the body has also been lasting better than my last gx body. The stc6 light weight body weighs the same as the lw gx body, but the 1mm sweep wing is twice as heavy as the flimsy pf wing.