Sounds neat... but why not just make it a targa? There is already a kit for the cutting and the insert available.
For a T-Top you will probably have to fabricate the opening and the inserts themselves because it seems like every small car that ever came with T-Tops is still larger than the GT. You will have to reinforce the car similar to if you were making it a convertable as you will be removing allot of structure from the roof.
Have you put much thought/research to this? Or are you daydreaming?
i had an idea here why not take the targa kit but modify the inserts so they would be able to be used as a t-top instead that would be easier then starting from scratch atleast i think it would be.....just an idea.
i want to put t-tops because i have never seen an opel gt with them. i have found some web sites with t-top kits. but nothing for an opel gt. but they do customizing. i havent called them yet but im going to with in a couple of days. so i dont know how much its going to cost.
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.