Until a month age, I was in a similar situation, Mordant short 208 floor standers, and a tannoy centre,diapole sides/rears.I moved my 208 to the sides/rears, and purchased the RP280 for the front,504 for the centre. In your case, I would use the Yamaha on side or rears for now, and upgrade to Klipsch on the front, as this I feel would give you greater benefits, but as usual, it all comes down to cost.