Upgrade my Minx speakers

Hey,

Im looking to upgrade my 5 min11 speakers, I bought the Minx speaker package with the X200 sub and a sony amp.

I want to keep the Sony Amp, also will keep the sub as i don't really have it turned on always.

My budget is around £500 for the 4 speakers & 1 center speaker. I want somthing not too big and also in white if possible!

I was looking at just upgrade to the MIN21 but wondered would it be much of an upgrade?

The speakers will only be used for mainly movies & games, I never listen to music through them.

They will also be mounted onto the walls.

Any ideas?

Thanks in advance!