Being an old guy, I'm more conservative and practical in my thinking than most of the younger guys on this forum. Just thinking about all that work, dollars, and the mine fields you'll have to negotiate with all those mods and tuning, man....... I cringe. You drive to a higher or lower altitude and the tune better follow suit, and the air/fuel mix better change as needed or meltdown is not far away. And then I think about the factory turbo'd cars like the Sub'y WRX Sti (up to last year) and the BMW 335i that have had big problems, requiring engine replacements. All the factory R&D dollars put into those models weren't enough to prevent big reliability problems. And you are going to build up a system with various turbo components from other models? Wow, my hat is off to you for your courage!
Then there is the consideration of selling the car in the future. We've all read that the resale value on a highly modded car will plunge. Nobody (or very few) want to buy a modded car knowing the stress placed on the motor and the likely or perceived driving style of the owner (balls to the wall). You could always remove all the performance mods and try to sell them at the time of sale I guess. Good luck on getting back much of your investment.
I think the biggest bang for the buck would be a 100-shot NOS system with tune. But again, you takes your chances the delivery system stays accurate. But like I said.... I'm old (66
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