Why would you want a twin turbo GT-T? Well in that case it would be a GT-TT lol...... In saying that it has been done more than once on this forum and was no advantage over the single!
I think this thread has been full of opinions and personal beliefs on a question that is really not going to get a correct answer.
DO your research and learn what cars can and cant do, the 1000hp number gets thrown around a lot but very few will ever get there in a street car as there is no point! That and the fact that to do it Legally is impossible as far as i am aware!
Twin turbo commy would just make a shitty car, expensive!