You have a good receiver and some fairly good speakers, except that your CS10 center speaker may be a weak link in the current setup. The CSi A4 is much better IMO.
Your front speakers have 91 db/ watt sensitivity, so more power is not a primary issue.
A high-quality 2-channel amplifier would IMO improve the sound quality, and improving your front speakers also will, but what you have now is good enough that you are looking at an expensive step up for a major audible improvement.
For a power amplifier upgrade, I would suggest a Vincent SP-331 power amplifier, which goes for $1299. It was voted Amplifier of the Year by the editors at The Absolute Sound a couple of year ago. That award usually goes to amplifiers costing 3 or 4 times as much.
Putting a good power amplifier in the front 2 channels not only improves the sound quality there, but allows your receiver to deliver more peak current to the other 5 channels as needed.
If the Vincent is more money than you want to spend, the Marantz MM7025 is $799, and might be a good choice.
The speaker upgrade could be any number of speakers, but one I would recommend is the KEF iQ90, which you can get for $450 each at KEF Direct. Those were selling for $1500 per pair, and they are a great deal now since that line is being gradually phased out. They are excellent speakers. The Q200c center channel speaker should be used with them ($449).
If you prefer to stay with Polk speakers,I would put in the CSI A4 center speaker first and see how much of an improvement that makes. Then I would consider the TSi 500 speakers.
Edited by commsysman - 8/12/12 at 6:29am
Originally Posted by Badblue6
Hello, I need help upgrading my audio setup. I have an Onkyo 709, polk tsi400, cs10, tsi200 (rears), owm3 (front heights), and hsu vtf3. I want to improve my systems musical performance. Ive been told I need a seperate amp for my font 3, but I listen to music in 7 channel stereo ,and movie watching is secondary for us. Do I really need more power to my center for music? What about amping just the front 2? Or should I spend the money on upgrading my fronts?