You don't have near enough amp to do the KEF's justice. You need a lot more current. Also, with a room that large and your music preference, perhaps might want to check out some horn systems like Klipsch or JBL.
Just as an aside, I am a KEF fan and currently have the R3 Meta speakers, However, I also have an M80 Yamha amp that outputs well in excess of 300wpc to 4 Ohms.

