Exhaust check
 

The exhaust system will be dual all the way back with an H pipe

For a 6.0 NA I want 2.5" and for a Radix'd 6.0 I want 3"

That sound right?

Are you planning for a Radix down the road? Either way, I'd go with the 3" exhaust. Any reason you're not going with an x-pipe?

From all the reading I've done hp between are close, but the H pipe give a much deeper and more muscle sound and that's what I'm going after Its well worth the couple hp I give up