I'm thinking about buying Sonos Arc, I don't have that much money but I wanted to invest in it, I saw some videos, and they say that with two more OneSL the Arc's sound doubles (at least in music), is it true? and is it worth buying these SLs? (I already have a play:1, is it worth buying the second one instead of the two Sls?)Or should I wait a little longer and buy the set with the Sls and the sub?And by the way, is the Sonos Amp worth it for this surround?