New here ...need some opinions

I have a onkyo 705 and i think i over bought on speakers.I bought a pair of Klipsch KlF-30's for my fronts.I have them in my HT system now but they over power my other Klipsch SF-2sides KlF-C7 center And SS-5 backs and a Velodyne va1250x sub.I have an older Yamaha rxv640 laying around and was wondering if it would be a good idea to hook up an amp to that reciever and use the klf 30's for 2 ch stereo.IF so money is kinda tight.I have about 800.00 bucks at the moment if i get an amp what would be a good one for those speakers.Any help or opionions would help.Like i said i am new to this i dont know a whole lot about this stuff
Before you spend a dime ... you should be able to adjust the volume output of your speakers relative to each other. For example, set the fronts at 6 and the center at 9 and the sides at 8 or whatever sounds best. Have you tried that with your Onkyo? The user's manual can walk you through that.

Yes i did all that.I can get it to sound good by doing all that but i feel like i would get better Performance out of them if i just go to a 2 channel setup.Is there a way i can use those speakers with and without an amp?When i am watching movies run them with just the onkyo then when i want to listen to them in stereo with a good amp just switch it over without having to swap the speaker wires from front to b speakers?The klf'30 will play continuous @ 200 watts.I know that my reciever is not putting out anywhere near that power.Thats why i was thinking of just using them in 2 channel setup with a nice amp.
If your Onkyo has a set of pre outs for front right and left you can run those out to a separate amp, basically bypasses the internal amp. I did this on an older model Onkyo before HDMI.I am not sure if this will affect how the speakers work with the surround processor though. It definitely improved the sound of the speakers in my setup.