I believe the reason the inline-6 out performs the V-6 with the same mods is that the inline-6 has all six cylinders pushing one turbo vs. the v-6. The V-6 has 3 cylinder pushing one turbos. Of course you can put larger turbos on the V-6 but than you have 3 cylinder pushing a much larger turbo and you know what that means, then, Lag! Usually when you do this you major high end but you lose your low end. It’s just a theory. I haven't researched it enough to say it's true.
