Upgrading from Mission to Polk

Legolad
Legolad Posts: 1
edited May 2010 in Speakers
Hi folks,

I'm thinking about replacing my front and center speakers but I know less than nothing about things like resistance and balancing the power requirements.

I have currently have this setup:

AV RECEIVER
Yamaha RX-Z7
Minimum RMS Output for Front, Center and Surround = 140W
(20 Hz to 20 KHz, 8 Ohms)
Dynamic Power (IHF) for Front L/R
8 Ohms = 170 W
6 Ohms = 205 W
4 Ohms = 265 W
2 Ohms = 345 W

SPEAKERS
FRONT L/R = Mission 771 (8 Ohm)
CENTER = Mission 77C (8 Ohm)
SURROUND = Mission 77ds (8 Ohm)
SUB = Outlaw LFM-2
150WRMS; 800W peak
Crossover Frequency: 30Hz to 90Hz and Bypass

The front and center speakers have always seemed a little weak-sounding to me and I have a chance to pick up the Polk Monitor 70s and the CS2 Center pretty cheap.

Would you consider these to be an upgrade from my Missions?