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

Yes, the Sooner monitors are absolutely killer. I fell quite hard for them when I first heard them but the $7K asking price gave me pause. They have some of the most beautiful, expressive, and airy highs I've heard. So much so that at first I thought the mids and bass were lacking a bit, but it was just that I was hearing, for the first time, some excellent rendering from the upper mids and highs. A great choice if you can afford them.

As for the power hungry Elacs (85db) I have no problem driving my 85db Clearwave Duet 6 monitors to lease breaking levels with my 90 watt Marantz integrated. 😃 That Well Audio integrated should be able to handle them.

All the best,
Nonoise

I second the nomination of the Elac Adante AS-61 monitors. The first shipment will be coming in sometime around 11/16-11/20 and every week thereafter. I, myself, am waiting to hear them as I liked the floor standers. 

They're a there way design with a sealed box, something that you don't see much of with monitors. They vent via the passive bass radiator on  the front (the actual bass driver is situated behind it). You'd save $1.5K and just may like it.

Another one would be the Studio Electric M4 for around the same price as the Elacs and they, too, are a sealed design. I've yet to hear them but the chatter is they are very good. I'm lucky in that I can listen to both in my area. Try to audition before you commit.

All the best,
Nonoise