BookShelf or Floor Standing Speakers

Thanks guys.  You are correct that I need to listen to floor mounts.   I do have the room for them.  The bass is what interests me most of floor vs let's call it bookshelf or full range bookshelf.  I don't need earth shaking bass, but enough to play lows.  Mostly acoustic stuff.

A lot depends on how in love you are with your current speakers- especially if what you are mostly looking for is better/deeper bass. Floor standers will probably give you that, but not by a huge amount because there will still be only two of them. When it comes to bass what matters more than anything is having at least four widely spaced sources. So you may want to consider adding four subs, also known as a distributed bass array, or Swarm in this case. https://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/

But if you are not that in love then you just need to do what you already know and search out as many contenders as you can find to audition.

Whether floorstanders will be an improvement is highly subjective as noted above. Even though I have a fairly large room, for my budget, I prefer standmount speakers with subs.

I found that MOST of the more affordable floorstanders (under $5K/pair) have compromises in the cabinet construction that cause audible resonance. This prevents them from achieving transparent imaging. Some exceptions can be found in small floorstanders, for example, the Spendor A7s. However, at that size and cost, you can get nice standmounts and two subs that might actually perform better in the bass. Of course, if you prefer a more streamlined solution, floorstanders have the advantage.

Generally, I find that small/medium monitors are better at disappearing as sources of sound, for any given budget. Their cabinets have less surface area that can be excited into audible ringing/resonance.

OTOH, large floorstanders (with large drivers) play music with greater scale. On average, they're also more sensitive, and therefore, can better produce dynamics  at low volumes. 

My preferred compromise between these two extremes are medium-sized standmount monitors with large midwoofers (8 or 10"). I also prefer the "lossy," damped cabinets that are designed to flex with the driver output, rather than mitigate resonance through heavy panels and bracing. The latter tend to produce cabinet resonances in the 500Hz - 1kHz range. The problem with that behavior (depending on the Q), is resonance in those frequencies sounds like ringing and grain to the human ear - it interferes with the frequencies where music tends to have greatest energy. Ultimately, it leads to listening fatigue, IME. Unfortunately, that is the chosen cabinet design for many floorstanders. The ones that are thick, heavy, and braced enough to practically do away with resonance are expensive.

In contrast, the "lossy" cabinet designs, pioneered by the BBC, tend to produce resonances around 250Hz or lower. The human ear associates this frequency range with the music's "body" and bass overtones. It does not impede on the most energetic areas of the midrange, which is why a $4K speaker with of this design principle can produce a midrange on-par with six-figure speakers. 

Like most aspects of this hobby, there are compromises that must be weighed against the listener's preferences. I prefer to own 3 pairs of $4K standmounts that I can rotate through my systems to keep things interesting, rather than own one pair of $12K floorstanders that could potentially give me the best of both worlds with scale and imaging.

If I got rid of my stand mount Ref 3A de Capos i would go with Pi 4's or Altecs or something big and hi-eff like that

Generally speaking  
  

• Bookshelves give better bang for buck (most $1000 bookshelves sound better in their frequency range than towers) which makes sense, especially factoring in shipping.  
• Towers have more bass, varies from a little to a lot.  
• Towers have a bit higher max SPL than bookshelves from the same model line. 
• Bookshelves are more customizable to your listening height by simply buying the correct height stands, some towers may have their reference axis too high/low, which would require tilting and whatnot, which can only help so much.  

Depending on the budget, I usually recommend a subwoofer anyway, so the bass extension benefit of towers is mostly negated, and crossing over bookshelves will add a bit more SPL (unless already maxing out wattage handling).