How much of a Factor is the intake on a forced induction engine (TPI) ? I know the factory TPI is not real good N/A . Just curious as I am planning on getting a Pro Charger

 

TPI will still be a restriction up top, if that's what you mean. How much depends on what type of forced induction and it's power curve as well. As with everything else, you have to have a matched setup to get optimal results.
Typically, you'll have a more power up top, but more everywhere else too, while in boost.
There are lots of people on here with TPI and Prochargers, I'm sure some of them can chime in with their results, or you can search.