Jm lab chorus 715 vs 725 and psb silver stratus???

Hi, currently im having a small bookself jm lab chorus 705 which is really good at high and midrange; however, because of the small size woofer, the speakers dont have a lot of bass extension or deep bass. Therefore, im looking to buy a bigger floor standing speaker which could give me a better bottom-end but still keeping the nice natural high and midrange. I went to a local speaker dealer and found myself interesting in jm lab chorus 715 for $600, 725 for $700 and psb silver stratus for $475. All of them in like new, store demo condition. So i need some suggest from people who been using or used them, and how good is the price? Too much or it about right? Thanks
you won't get a ton of low end out of the focals--they're rated only in the high 40s. the psbs will go lower; however, since you like your bookshelves, i would keep them and augment them with a sub--you can something like a hsu or a paradigm can be had very inexpensively.
I own the 9XX versions also called Flectras in their day. The Bass goes to the high 20s low 30s that's it, but I really love them. Various people suggested the sub for the very last octave but I have held out. You may want to explore used 9XX series that will get you close to absolute zezo plus a lot better mids and treble.