worth the jump to Cornwall IV's from Forte IV's?

I agree that Cornwalls don’t plumb the depths but they have very defined bass down to the upper 30s. I used subs with mine, but they weren’t necessary to get very satisfying bass. And as @mwjones stated, the bass of the LS can be surprising too. I can certainly see why some people don’t use subs with them depending on your musical taste.

I’m thinking of upgrading from heresy to forte, what is your specific feedback on this? In my other room, I upgraded from cw to la scala-oh my my!!! La scala are the only 3-way horn loaded speakers (with k-horn), and it’s so unbelievable!!! Do it.

Aside from being an incorrect blanket statement, do you see your second sentence is a non sequitur to the first?

"All Klipsch speakers need Dynamat placed inside the cabinet to yield the best results. Ive had ALL of the Speakers mentioned above except the La Scala’s and Heresy."

My Forte IV, La Scala II (two pairs) and Heresys never resonated or needed anything from me to sound great. 50 year old Klipsch (like any other old speaker) may need some acoustic treatment for best performance, but the op is discussing new speakers. I don’t think Ozzy or I have used Dynamat on our horns.

Greg makes several Volti speakers which are as large or larger than the Klipsch counterpart they are modeled from. They are great speakers in their own right.

I live alone and never had an issues moving any Klipsch speaker.

And its a problem the Forte is unforgiving for poor recordings? What the solution; buy poor speakers so you don’t notice or stop listening to poor recording? You chose.

Horns match best with horns full horn loading is the best way anything else is a compromise.

No clue what you Guys are talking about. I run CW4's with a 500W Orchard Audio Ultra Amplifier and easily plumb the depths at around 30Hz (with in room gain/no eq bass boost applied of course). I definitely do not need Subwoofers in my rig. 

I can "shake the foundation" all day and night !