I finished reading all of the guides but I still wonder: What is the difference (preferably charts) the twin-turbo system produces in each stage (stages 1-6) compared to a twin-supercharger system (stages 1-4). Also, I apologize for not making myself clear when I said the term "fuel economy". What I meant was which one is more fuel-efficient compared to the other, not the MPG. Also, are there any installation manuals/guides/videos for the twin turbo kits/ twin supercharger kits from Fast Intentions or GT Motorsports? The only one I could find for a twin-turbo kit was here:
DIY GTM Twin Turbo Stage 2 Install!!
Thanks to everyone who beared with me!