Great list of mods you have lined up! If you already love the Barton shifter, than you got to check out the shifter bracket. Slamming gears is surprisingly easier with the shifter bracket, especially 3rd gear.
With 8psi and LT headers, you should see right around 600rwhp with the Procharger kit. In fact, I think you could easily make 590rwhp with a very safe tune.
Lastly, I suggest upgrading your stock two-piece driveshaft to a one-piece aftermarket unit. With those power levels, it won't take much to snap the stock DS at one of the joints. Especially if you plan to hit the drag once in a while.
Hope this info helps!
I like to sounds of your setup as well! The only thing I wanted to point out or suggest was upgrading to the RXT clutch instead of the RST. The RXT has the same street manners as the RST and it is a lot more resistant to heat. I prefer the RXT because it allows you the ability to slip the clutch harshly during drag launches and withstand the heat without glazing over.
Don't get me wrong, the RST is still a great clutch. IMO, if you're going to purchase the RST, it's better to take the next setup for to RXT!
Just got a call from the Ford dealer, they said I need dowel pins? (Spelling? ) I thought that was included with the clutch kits on the 2011 up mustangs? It says on the box they come with them but they said they aren't there