Hi Kazz and JohnA,
Got my 2nd XS30 on Friday and am enjoying them very much.
I tried the original one in several positions including corner and various distances from the corner but found between the speakers worked best, which sort of amazed me. As Peter suggested to me a sub of this quality and power doesn't necessarily need the corner loading.
As I said earlier my set up with the two subs is the same as Kazz's, although I don't have a cabinet in between.
All my listening has been 2ch music, I can't imagine what they'll sound like with movies. Also haven't done any room correction yet but will do so soon.
Glad to hear that you're happy with the twins, I haven't listened to much two channel but they are awesome with HT.