Please suggest bookshelf with best bass response under $4000 pr.


Lately, I've been craving deeper, tighter bass. I'd like to hear some ideas for replacing my Silverline 17.5 monitors. Is this a stupid question, due to inherent limitations of driver size imposed by typical bookshelf dimensions, or might I actually do better with another speaker? Amplification is Wells Audio 150 watt SS Majestic integrated. Source is aging Jolida JD100 tubed cdp (in new year, I plan to replace this with another SS cdp or a transport/standalone dac combo). Thanks ! 
stuartk
Check out Legacy Studio's Studio HD's.  Strong bass down to 40Hz and a very good looking speaker that will blend in with your wife's room decor. I have compared the Studio's to Kef, Revel, and most other bookshelf speakers... At less than $2000 for a new pair in the Rosewood or Black Pearl finish they're hard to beat.
Acoustic Zen adagio junior or Bryston Mini T, They are substantial big for bookshelf speakers but will bring you deep strong bass  as stand floor speakers .
There are so many really amazing bookshelf speakers e.g. Kef, BW and so on.  I would try to listen to the newer Elac bookshelf speakers designed by Andrew Jones.  You could save the extra money for a subwoofer (again, so many great designs) to take care of those frequencies that you can really feel.  Again, check out Elacs sub offeringa as they are so cost-effective.
Lastly, matching your amp to the speakers is critical and there isn't a better method than listening to the setup.  If you can find the right dealer they will accommodate you.  When I purchased my last speakers I carried my (heavy) tube amp to two dealers who wired it up for me to really get the sound I was listening for.  Take your time...  and enjoy!