Better Amp for Cornwall IV's...

You really need to look at the measured impedance curve.I tried to find these measurements but had no luck.If the impedance does not dip below around 6 ohms then an amplifier with a highish output impedance [typically tube amps and not SS /class D amps would be the best choice].It would seem pretty silly to make such a high sensitivity speakers not to suit those types of amps but it is possible that is what Klipsch have done.If the speakers sound a bit weak or dry in the bass that is probably because the amplifier being used has too low output impedance.Which is typical of SS amplifiers including most class A ones .Adding more power will not fix this because the bass response is overdamped by using that type of amp.
If you do not want to use a tube amp then the best choice would be a Bakoon SS amp which operate electrically more like a tube/SET amp and which are current drive and have high output impedance.[Just about all SS amps are voltage drive/low output impedance]The Bakoons also sound superb and are a compelling example of why current drive /zero negative feedback/high output impedance amps sound best [if your speakers suit them and most mainstream speakers don’t].

Yes the Klipsch site gives you absolutely no help in terms of some pertinent specifications. I think they something to the effect that some or all of their speakers are 8 ohm compatible or some such nonsense. I pretty certain that the curve of most Klipsch speakers are not ideal for tubes but the high efficiency will cure some of the other ills. 

I was fortunate enough to spend a few hours listening to Tri Mai's system a few weeks back. Tri is the owner of Tri-planar tonearms and I had one of his arms put on my Merrill-Williams table. Tri has a very impressive horn system that I think would make most horn enthusiasts drool. He uses modified Classic Audio speakers with Atma-sphere Novacrons (OTL) and a MP1 preamp. For what horn lovers like I havent heard many systems that deliver in these areas better than this system. 

I assure anyone who cares that the Cornwall IV can achieve extremely loud levels with only 20 watts of tube power in a relatively large room. I do it all the time.

Six months of listening to the cornwall iv’s paired with a mc275 MK VI and a c2600 preamp has definitely changed my attitude towards tubes. 

@OP,  

I have the Cornwall IVs.  I agree with so much above.  They are very versatile--you could swap amps to your hearts content to change the sound.  

How big is your room?  How loud do you like to listen? 

I do think you should try tubes or Class A.  

I have a 300B SET that sounds great but it's not enough power. I know folks will say that's sacrilegious, but it's true for me and I don't listen that loud.  I do like it, but I prefer my Primaluna integrated (modified).   

The thing with the Cornwalls is they are so efficient you are really going to hear all of the amps positives and shortcomings. 

I hate to spend your money... but if I could...are you open to trying different stuff?  I think you might want to.  Some solid state offerings can sound dry, brittle, harsh (you name it) with these speakers.