Texas850Turbo

Sorry in advance, but I had to do this...

couple issues I see:
How did you pick that supercharger?  Did you look at the performance map for it?  I was curious and looked it up -M45 map
Let's also take a look at the 15G comp map-
15g comp map

So let's take an example of an operating point- 350 cfm through the 15g, 10 psi boost (1.67PR), this puts you at 67% efficiency, sounding good so far.  Then you hop over to the M45 map, okay, 350cfm inlet flow, which is 600m^3/hr, and you say you want 20 psi manifold pressure, so you have a PR of about 1.4 across the blower, wait... that's barely on the map, and you're at 15500 blower rpm(is that even possible being driven off the accessory belt?)... and at 45% efficiency, which when multiplied with the turbo efficiency and assuming a 70F inlet temp leaves you with a 510F (calculation) supercharger outlet temperature.  

In summary you have a couple problems:
1. supercharger needs to be driven at twice crank speed to get your airflow requirements
2. at that point it's incredibly inefficient
3. your cooling requirements are then massive

I think you should rethink your supercharger choice, and why you put it after the turbo instead of before, and why you need a twincharging setup if you're already running nitrous...
Also, the reason most twincharger setups you see have the blower feeding the turbo is that roots blowers need to be kept cool, otherwise the vanes expand from heat too much and interfere with the housing, which can jam the blower.


Don't get me wrong, twincharging is awesome, but it requires a lot of planning and careful component selection.  There's a reason you don't see it very often- it's very difficult to get working correctly!  I wish you the best of luck with whatever direction you take...