As said in another post, I am going to purchase a 2-channel amp to add on (for my front mains) to my HK avr 520 so that I can do 7.1 My speakers can handle a max of 400w...how big of an amp should I use. I really don't want to spend over $500 for it...probably purchase it on ebay. I was looking at some of the carver tfm-25 or tfm-35. I guess i'm just trying to figure out how much louder and cleaner 250w is compared to the 75w on the hk. Any suggestions?