A better receiver *might* bring out better sound...it's not a matter of power but how accurate its output is, and whether it can deliver that output to your Studio 60's. So a good receiver like a Rotel that's rated lower in power may actually sound better than a more powerful Yamaha.
But in terms of power, you have enough power if the receiver isn't overheating or distorting when you play it at your normal listening levels.