1. Do you really think the S60 at 10psi could sustain enough airflow (CFM) to supply a 2.5L DOHC motor? IMO it can not. Maybe? if you dropped redline to 5k, but the turbo needs to be choosen to complement the engine design, not vice-versa... The engine is designed with a 4-7k powerband (stock) - it would easily pull past 8k
if it held together!!! Putting a turbo that changes the power band to 2-5k (
even 3-6k) would be working against it's design and sacrificing it's high rpm breathing prowress. Not to mention the cams!
2. We both agree on the VVNT part (lag time for compressor spin up, etc) - we just are talking in circles here...
3. :p Theoretically of course...

4. You missed my thinking. You are implying changing the cams (intake atleast) to have less overlap. That would increase the cost exponentially. I'm talking about having to make do with the longer duration cams the SVT has and making up (compensate for) the lost cfm flow via a compressor with a higher CFM/lower boost map.