Alternatives to McIntosh MC402?

My main amp is a McIntosh MC402 power amp, bought new about 18-20 years ago.  It's performed flawlessly since day one.  I no longer have the packaging or manual.  I use it to power Sonus faber Olympica III speakers.

I'm contemplating a change of amps. I'd like to get something physically smaller than the 110 lbs. MC402.   Perhaps 50-60 lbs. max.  I could go with another power amp, or an integrated.

The amp would have to provide ample power to drive somewhat difficult speakers,  Though advertised as 90 db efficiency, I've read reports that the SF Olympica III's are actually less efficient than that.  They are rated at 4 ohms, but evidently the impedance dips into the 2-3 range.  We listen frequently to symphony, opera, and hard rock -- demanding music with big dynamic swings.  

Sonically, I've been pleased with the MC402.  It's powerful, authoritative, and cool-running.  It matches well with the SF's (though I realize that many audiophiles might find the Mc/SF combo dark, or veiled, or the like).  

I have no particular desire to throw large sums at an amp; I'd sell the MC402 and use the proceeds to fund most of any new purchase.  I am OK with new or used in good condition.  It may be that there is no attractive alternative -- a power amp or integrated that can be had for, say, $5K at most, that will provide sufficient power and sonic satisfaction matched with the SF Olympicas.  But I would appreciate your suggestions.