There is another route to take...if you have pre-outs, buy a cheap separate amp to drive them. I was just given a pair of Yamaha floor standers which are 6ohm, plus i drive 3 sets of speakers in other rooms

Instead of replacing my 1980s receiver, i purchased a NAD 902 off ebay for $105 shipped. I run it to all the speakers (via speaker selector) and it does a great job without straining my vintage receiver.