$8k for speakers - new or used

Speaker

Yamaha NS-5000PNST 3-Way Bookshelf Speakers with Stands | Hi-Fi Heaven (hifiheaven.net) $9,599.00

Need room for the "bookshelf" speakers to breath. They are big.

Used N803D is very simple step up. 

For detail and punch, Monitor Audio Gold 300s might fit the bill or a set of used Monitor Audio Platinum 300s could be worth considering. I think they will have the speed and detail of your current B&Ws but just on the right side of the warmth vs harshness balance to my ears.. Speak with John who is the owner of The Audio Connection which is just north of the U-District. He can sound opinionated, but with respect to sound quality, his opinions are generally right on the mark.

You might want to attend the Pacific Audio Fest, which is happening on September 6-8 in Seattle.  Doesn’t look like a huge show, but gives you unique opportunity to listen to a wide range of speaker types - perfect timing as you’re considering something new.