We walk you through the process of manually calibrating and level matching your speakers so you can double-check the results of auto-calibration. You'll just need an SPL meter to get the job done.
www.audioholics.com
Here is how to do it. You would need a spl meter.
This can be a redundant advice but if the retailer tries to upsell you expensive cables of any kind (power, interconnect, speaker), then stay away. They have no effect whatsoever on the sound quality. I found retailers who push expensive cables to be questionable at best and unethical at worst.
Also just to be clear, if you have the fund and if you want to, adding a good power amp definitely does not hurt. In case of denon avr which is known to run hot it can help to cool it down. Some people would even say that it reduces noises that added by other channel amps. I just don't think you need it. You can just start with a good avr.