5.1 under 4k?

Listen; you only get a deep and wide stage wenn; source, amp ( even pre amp and power amp), speakers en even cables can give a deep and wide stage. Wenn one part is not capable of giving depth, it is gone. Wenn you put a poweramp like Pass Labs or Primare to a Marantz surr receiver the depth is gone. I have done these tests also many times. Onkyo is the only brand in there price tag which is capable of giving a deep and wide stage. Many of my clients have an Onkyo surr processor with a Primare power amp with Monitor Audio. They all have a 3-dimensional deep and wide stage. I love to give clients for normal prices a 3-dimensional sound. Most of there friends all have a 2-dimensional sound. After hearing a 3-dimensional sound you want a 3-dimensional sound as well!

You have pre outs for all of your channels. You can get a separate amp of any of them and still use the amps in your 7007 for any of the channels you don't get amps for. For example, you can buy a 2 channel amp for your front left and right speakers and still use the 7007 for the center and surrounds.

How do I tone down an amp to not damage the newly purchased speakers? I'm considering purchasing an anthem mca-30 for the front 3 and let the receiver power the surrounds. Opinions?

Thanks again

Wenn you have put on the connections right it will nog be a problem. Your speakers need about 300-350 hours to break in. In the first 24 hours you will hear the most difference. The humm in the low freq. will be gone after one day. After one week the high freq. will be less harsh. Mid freq. cost the most time. About 300-350 hours. MA speakers can be played a lot louder than most of there competitors. I never had a client who did blow them up.

"How do I tone down an amp to not damage the newly purchased speakers?"

That's not a problem. You adjust the gain for each channel using the preamp in your Marantz just like you normally would. The best way to not damage your speakers is to listen to them. You should easily be able to hear if something is straining. If it doesn't sound right, turn it down.