Suggestions for bookshelf speakers that have great dynamics, budget of $500 used.


So I really do not know where to start with bookshelf speakers as not been in the market for any for ever it seems.
This is for a second system where a pair of Monitor Audio Silver 3i are currently doing duty.
Room is largish and open but ultimate sq is not the aim as it is occasional use only, but when I do fire this rig up I usually like to play fairly loud.
Sources are many, fm radio, cassette tape, vinyl and streaming.
I have plenty of horses to feed them so even inefficient models can be considered.
Prefer to buy used as big savings to be had obviously and already broken in.
So suggestions around a maximum price break of $500 used.
Thank you in advance.
128x128uberwaltz
Have a look at Silverline.  Although perhaps better known for floorstanders, they make some good bookshelfs; you might find a used pair at your price point.
I have a pair of modified Heresy IIs, that might interest you. If you have any interest, you can PM me.....
I own a pair of Dali Zensor 1s. I purchased them used ($200) from another AGer who wanted to upgrade to the Zensor 3s. The 3s would be better for a 'largish' room, however can't say how they would compare to the Monitors.

A used pair of Paradigm Studio Reference 20s V4 might be just the ticket. I once owned a pair and thought them to be quite dynamic. 
Zensor 3s are nice mellow, have Paradigm 20 v.4 love em! MA Silver also tried, more laid back than Paradigm. Might try again!
I sort of figured the Zensor 3 would be more suited to my room tbh.
Silver line is definitely an option, a few on USA audiomart in my price range.
Not heard any paradigm speakers, will research them.