What is the difference in the Vortech V-1 T trim & V-2 SQ besides the SQ be quieter?

ATI P-1SC vs D-1SC. I hear the P-1SC makes better power in the lower rpm range. I have a 3500 stall, would the D-1sc be a better match?

Which S/c is quieter? ATI or Vortech?

I see a lot of LS-1's running 8psi safely, is this psoobile with stock bottem end LT-1 or is 6psi what most are running safely?

Is an aftercooler necessary with the Vortech? I see the aTI's come with 2 intercollers.

How much is a typical bottem end rebuild to handle more boost?

I just started researching the S/C idea, so these are some questions I have after doing so.