The GTS badge that krzysiu posted up is the one I didn't like because it looks blatantly fake.
here's one of the the vector designs I used for making the SAU logo ages ago. I made the S sorta using the same curves and dimensions as the font of the original GTR logo. Its fairly easy for me to swap the R with the S to make up a GTS logo, the only problem is converting that concept to a prototype for a badge.
Also something to note is that the R32 GTR logo is different to the R33 and R34 ones, the one I've done is based on the R34. So guys with R32 GTS' might not like em (if you're as pedantic as me about these things).
I've done some casting and resin work before, so I'll give it a shot, and see if I can knock out a prototype.