Well if you know about turbo design, then a twin scroll exhaust housing allows for quicker spoolup then a regular exhaust housing, this comes into play when you use a larger exhaust wheel, like the one on this turbocharger.

Now this turbo is built alittle different then your average T3/4 or T4 designs where usually the exhaust wheel is smaller then the compressor wheel. What the turbo builder tries to do is give you the response you want by using the smaller exhaust wheel in a lower A/R exhaust housing which increase exhaust flow hitting the exhaust wheel, making it respond faster, IE quicker spoolup.

In the case of this TFO7/TDO7 hybrid, its using a twin scroll exhaust housing larger exhaust wheel with a smaller compressor wheel. The twin scroll splits the exhaust flow into two smaller chambers both aimed at diferent point on the exhaust wheel making it spoolup reasonably quick for such a large exhaust wheel, verses a regular exhaust housing same A/R. This design idea comes from Semi-Trucks needing a better rpm response due to the fact diesels dont go past 3000rpms because of the stroke to bore ratio.

So look at it like this twin scroll exhaust housing with a large exhaust wheel, and a smaller then normal compressor wheel being used in this application means alot more torque then a turbo its size will be produced. Why? Simple the Exhaust wheel is much larger then normal turbo designs being built and when you use large exhaust wheels torque numbers go up. ALso the fact the compressor wheel is smaller in diameter means less wieght and resistance so you will get a stronger mid range to top end will be the over all effect.

I have seen all of this demonstrated using a TDO6-17C which was stock turbo on a Syclone/Typhoon. TDO6 exhaust wheel is larger then your TDO5 exhaust wheels. 17C wheel is same diameter as a Super 16G wheel with a different blade design. none the less the theory above I just explained applies here.

Also if you want another application just look at the EVO VIII turbo design it is a Twin scroll exhaust housing design, using a smaller compressor wheel diameter then the exhaust wheel.

Hope this helps you understand why this turbo design might be more then what you thought.