Turbos make more power and are easily tunable. Not to mention the incredible amount of work to try to mount a blower. And as far as a centrifugal blower- it's basically a turbo compressor driven by a belt and is NOT linear like a PD supercharger. There is absolutely no reason to move to a blower. As far as arguments about instant boost at low RPM on PD blowers, that's correct, and is part of the design. Many people say measure the area under the dyno curve which purports to show that a supercharger is better. But actually you need to think about "where" you start measuring the curve. Are you racing at idle? Measure the area from the rpm where your broadest gear spacing will put you after an upshift at redline. On the ST that's about 4000rpm That's the only area under the curve that should be measured or matters. Of course, a car might "feel" a bit faster when you're tooling along at 2k rpm and hit the gas with a supercharged engine, but once above 4k, (or wherever full turbo boost is available) apples to apples, a supercharger is less efficient and produces less power. The ST with its head mounted small turbos hit full boost at around 2.6k.
