Even if you do just T-top a GT you still have to do all of the reinforcement to the body. You could modify the application of the Targa Kitt and convert into T-tops, but they will end up solid (no glass T-tops in other words). I know of someone who wants to sale a Targa Kitt its about 95% complete(less latches and instructions) he may have a copy of them in German if not they can be found. I am not sure of his price but I can put you in touch with him if anybody is interested.