Sonos connect speakers

[vxsmithers]

Looking at in ceiling speakers for my sonos connect. the span they are going in is quite a deep joist and about 4 metres long, would I benefit from an enclosed speaker, or is this really not going to make much difference? I don't want them to be too boomy which I'm guessing could happen?

Was considering monitor audio CT150 or CT165 - any better options around the £100 - £150 mark?