get a amp that's more powerfull than your speakers and turn the gain right down. you won't damage your speakers then and the sound won't clip like a smaller amp would. I was once told this in this example.
Drive a mini 100 miles at 100mph and it'd do 100mph for about 10 minutes and then blow up. Drive a ferrari 100miles at 100mph and it wouldn't bat an eyelid! Same with amps and speakers. More power down turned down. ie, bigger engine running slower than flat out.
I had 40w RMS speakers in the front and they ran great at about half gain with 55w RMS through them. I bridged my 4ch amp to 2 channels, but even when the amp right down the speakers couldn't take it. maybe 110w RMS was a bit much.

Your headunit should run about 75% of it's volume range flat out. So my kenwood has 0-35 range. max volume should be 27 ish. That's what i was told. above that and the sound quality suffers.