maybe we need the exact specs on the variable twin system first. Next step would be getting a downpipe that can handle the pressure level and fittings for the supra. And then we could see what turbo's we can replace variable ones by. Perhaps with electronic tweaks, getting 2 big turbo's in...

two big turbo's is good for the long run but your car will lag off the line like a mother.... it wont feel like ur single right now... but the long run its better... also... im sure the 550 stock injectors could handle the job but u might wanna try 1 step higher.. go 750 or so. ... also u need to upgrade your fuel pump

I heard about putting 750cc injectors aswell. But if you upgrade the injectors and fuel pump and with other "tiny" tweaks... Could it handle double heavy turbo's in your opinion?

750's will for sure... they can get rather pricey though

I belive its by the air flow, dont know quite how they control it though..