Speaker/ sub recommendations

Hi

I have the following set up

Arcam Alpha 10 int (without DAVE module)

Arcam Alpha 10P  (3 Channel)

Arcam Alpha 9 CDP

Mission M35 (not 35i's) Bi Amped

Chord chrimson interconnects through - out

Cambridge Audio Ultra Bi Wire used for Bi amped

my room is 3M x 5X  and currently got the setup with the speakers accross the 5M length due to chimney breast.  Would moving the speakers across to the 3m width give a better sound? or should I look at better / different speakers.

 The problem...  I like the sound of the missions. but I listen to a lot of different music.  Most sound pretty good but now and again I feel I need a little more thump. (thinking maybe the m3as sub might be a worth a go) .. It's the only one I can find in beech to match my M35's lol.

I listen to anything from rock to reggae to classical to the likes of Maeve OBoyle (which sounds pretty amaizing)

Any advice welcome and many thanks in advance

Dave_Rave