Combined speakers yeild even better performance

The other day I decided to try something I've always wanted to try. I wanted to see what it would sound like if I added an Energy Veritas 2.2 (good quality bookshelf 3-way speaker) to each of my Thiel 2.3 front speakers. The Energy speakers are stacked on top of the Thiels (using spikes with protective disks underneath) and are slightly angled down toward the listening position using longer spikes in the rear.

The results were very surprising. The dynamic range was improved, and the over-all sound was more coherent and full. The performance was incredibly engaging for both music and movies.

The problem is, I'm stuck in a moral dilemma. How can a mess with the design of such a great speaker as the Thiel, even if the sound produced is better than before?

I'm wondering if anyone else has ever tried this experiment.
Stacking speakers can work very well and was somewhat popular years ago.

I once suggested in a thread here on audiogon forum that a member stack a pair of Vmps supertowers (he had a huge room with very high ceilings and wanted huge sound to match)..he probably thought I was off my rocker.

Is this what some Nestorovic speaker models are trying to achieve? I think some models come in pairs using inverted stacking.
The only speaker I can think of that offers the option of stacking two identical units inverted is the Morel speaker line. I had a chance to hear them at Sound Vision in SF and they sounded incredible. VERY EXPENSIVE!
Stacking used to be popular. At first they seem to fill the room with ambience, but, I've always tired of the sound quickly. There is a loss of coherence that nags at me. Line sources are one thing, but, hap hazard stacking never worked for me, and that it is so rarely seen today, I suppose for many others too.