Two audio places have listened to my system and have both told me the speakers are not getting enough power at high end, and I should consider amping them.

My problem is that the majority of affordable amps are 4 channels, and I obviously have a 7 channel amp, correct? My front doors are memphis PR's with a swivel tweeter in them, and I will probably upgrade the rears to 6x9's. What do you guys think, what do I do about loosing my door tweeters? If I have extra power to the door 2 ways I installed, will it compensate for the lack of tweeters?

Also, can I use the stock speaker wires with an after market amp?


Thoughts?
Thanks,
JIm