Quote Originally Posted by MSq5 View Post
I think that combo may bleed off excess boost, though. Might be mistaken.
Not sure when and where it may bleed off boost, but their site has a different power band curve than just the stage 2 supercharger pulley, so something is different.

Back to the OP though, there is no benefit to a DP versus larger single. So your answer to 1 - yes. 2 - none. 3 - more tuning for these mods can unlock more power.