I have Polk Monitor 30s for my fronts but I wanted to get a new center channel.Is it best to get same brand or can I mismatch,seems that some people do some don't .I was looking at a Klipsch SC-1 but wanted to know if I should get a Polk?I also just got these Monitors and now the store where I got them from has the the Polk R150s on sale and I could get 2 pair of the R150s for the price I paid for the Monitor 30s.Would I be giving up alot to go to the R150s,all around fronts and surrounds?