The Apple airport express will stream music wirelessly from your computer to your receiver. And it is also a wireless router. Then you can get whichever brand of receiver you want.
I agree with this. And to add. Headroom is more what you don't hear than what you do. No clipping, no distortion, no harshness in the highs, and no muddiness in the bass and midbass.
Sounds like clipping. I don't think your kenwood has enough oomph to run that speaker setup. You might want to consider a receiver upgrade or an outboard amp. For now set all of your speakers to small and let the sub handle the low stuff.
It should be more of a comparison between a vette and an economy car. Not all 4 cylinders are made equal. If we're talking a Suburu wrx sti the experience is quite thrilling.
back on topic now[]
You don't buy a Porsche just because you can afford the car payments. You also have insurance and upkeep. Do you buy a Porsche and not put 91 oct gas and synthetic oil in it. When the brakes wear do you run to autozone for replacement parts or Brembo.
Yes you can run RF7s with a low to mid level receiver(brand does not matter). But they won't truely perform without good quality amplification.
I'm not saying don't get the RF7s. I'm saying get the RF7s but plan on upgrading other equipment.