Sounds like you have the headers sorted out. A Doug's guilloutine style E-cut out would be a nice addition if you want to scare the neighbor kids / at the track.
There might be some gains left on the table with the smaller TB. I know that alot of people (CTVS owners) have seen better performance with the 102mm+ tb on the positive displacement blowers like the TVS 1900/2300/2650.
I bought a used Nick Williams 102mm from a local for my twin turbo CTSV build, but after talking to several turbo tuners they recommended staying smallish TB with the turbos. Apparently pushing the air into the smaller diameter helps with turbos ather than pulling the air in on the roots / PD blowers. So I stayed with the port matched LS7 TB on the LS3 intake.
The LS9 and Varimax intercooler pumps are a solid cost concious upgrades. You can be a baller if you went with an expansion tank and a reprogrammed Steward EMP pump or a badass CWA400 pump. Just be careful with your electrical system with the high powered pumps as they ran my battery down EXTREMELY fast with just the key on and not running / on a charger.
Yes the 20x10 rears with 315s are NICE. MT Streets is what I ran on the street. I swapped out to 16" regular trailblazer rims with M&H 275 DRs at the track. They hooked amazing with 18psi.
Good luck on whatever you do with!