I was using the 402a on my M80s and they sounded really good. You will need XLR male to RCA Male cables which cost me 20 bux. You would connect the rcas from the amplifer to the preouts of your receiver. I was still able to use my features on my receiver.

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=133649&is=REG

I would try the power of your receiver first and if that isnt enough you can go with the crowns. I purchased my crown amp for ~ $250.