I ran into the same problem when I was looking to upgrade my system, only I had already gone and gotten 4 ohm speakers. I searched about for a receiver that would handle 4 ohm loads, but ended up having to buy seperate power amps to smoothly handle the load.
I would recommend that you stay with 8 ohm speakers . . . . the amp sections in receiver aren't that great to begin with, and making life harder on them is just going to make them sound even worse -- I fear your speaker upgrade could be wasted.
I would recommend that you stay with 8 ohm speakers . . . . the amp sections in receiver aren't that great to begin with, and making life harder on them is just going to make them sound even worse -- I fear your speaker upgrade could be wasted.