I agree with most about each having its applications & advantages vs disadvantages. There are many things to consider.. but since you asked about TT vs SC, I will say some things which demonstrate how TT is more comparable to an SC than one T.
With a normal single turbo car, there is a compromise that must be made. Either it can have a small turbo which spools up quickly for less lag and thus more bottom end thrust, or it can have a large turbo for more horsepower & thus upper end thrust, but with more lag and less low power. Twin Turbo designs were created to address this compromise. By having two turbos, they can both be smaller than one turbo for easy spooling, less lag, and more low end power. Yet because there are two, they can still have upper end power like one turbo with their combined output. This spreads the power out over the RPM range. They will not spool up quite like one turbo of equal size, but certainly better than one large turbo. This is obviously beneficial over convential turbo cars, as demonstrated by the 3.0 liter, 4600 pound Mitsubishi 3000GT VR4 & Dodge Stealth RT TT. These cars run the quarter mile in mid to low 13s stock.. with more weight & a smaller engine than our cars. Other variables do exist of course, such as AWD traction and OHC.. but the TT design does help out with this.
So in the case of TT, I believe it can be very competitive in conventional street cars as the best forced induction system.. in terms power output. But as mentioned, there are still other issues which the Supercharger has an advantage. The biggest which comes to mind is reliability. A turbo must be meticulously maintained, or else it will likely fail. Over the course of its life, its also likely to lose noticeable function. A Super on the other hand can undergo significant abuse without significant damage, especially the Eaton unit. I have seen these things run without oil and live for a long time afterwards (refilled). The supercharger is also not restricting the exhaust (maybe the intake) and reinserting "dirty" air into the engine. Turbos recycle exhaust gasses which while efficient is sometimes considered a deficit for the engine. Superchargers will still also probably have more low power, and some might even be capable of producing more boost than some TT designs.
Just some thoughts..
I must have around 200-210hp in my stock SC. It’s a beast… But I love it.
