Is this Klipsch upgrade worth it?

Mofojo, my room is 16x16, with around a 12ft hole opening into the kitchen.

No I would not make that upgrade. I have heard both and the current La Scala (at two different dealers). The Cornwall iv and La Scala were in the same room with the same front end at both dealers.

The Cornwall IV has the potential to have harder hitting bass depending on the room. Get it just right (kind of close to the front wall) it hits harder. The Cornwall is a little softer in the bass on the leading edge but easier to place on the room and far less room dependent. If the bass is good with your fortes I would look at upgrading something else or saving and going for broke later lol. The mids seemed to spread out a little more on the Cornwall. Hard to say as they were in different rooms (heard them back to back though). 

The La Scala is a different animal and could be a worse speaker without subs. They have NO bass extension and need subs. I heard them without subs and they sounded really thin and dry to me. I felt like I could hear the wood but that could be in my head. Sounds different than MDF. They have a very strong horn sound, Wide soundstage that maintains focus. Listen before you buy for sure. With the latest price hike they are getting up there.

Not sure just how much better the Forte IV is over the III. I owned the IIIs for a while and thought they were very good. Moved on to Klipschorns then to Spatials. Came back to horns with the CW IV. My opinion is that it is definitely worth upgrading to.

I now own LaScala IIs and they were a very nice upgrade from the CW IV.

Oz

Oz.. that's interesting, the Spatials were one of the speakers I was considering originally.
I liked the proportion of the Cornwall lV's but was scared to shell out the additional dough because I didn't know whether I'd like the sound of horns.
The Forte lV's, to sound optimal, need to be moved into the room. I was wondering whether the CW's could sit closer to the wall in my room... and sound good there.

According to these guys, the difference isn't nearly as great as one might expect.

https://www.youtube.com/watch?v=XPJevbwL9VU