my take is if your going with the dual, you will need the rest of a package to benefit , (a couple step larger TB, and some headers), maybe even a cam.
Personally, i looking to get my plenum gasket replaced and work on my beer keg intake manifold a bit. and bump up a few more mml on the TB.
What i posted really goes either way, of coarse more in and more out gives you horse power. Basically the single will be best suited for higher rpm,and dual for lower... The M1 being gives you the best of both worlds, which seems most people like those, also they are bolt on with little mods.