Recommendations and thoughts for end game speakers and amps

Good morning all. I am looking at Rockport Avior ii speakers. My dealer likes Boulder amps with these but I wanted to get everyone’s opinion first. I will be getting an integrated with HT bypass. Right now I’m looking at the Boulder 866, Gryphon Diablo 300, and the Simaudio 700iv2. Has anyone listened to these speakers with these amps? I’m looking for highly detailed but not harsh highs and mids and outstanding bass as well. Basically a set up that performs fantastic from top to bottom. If you have any other speaker or amp suggestions please let me know. Thank you! 
If I'm reading between the lines correctly, I thought it interesting that in the recent Stereophile review of the Boulder, the reviewer found that it did not best the Krell integrated he used as comparison, just that the Krell was slightly warmer and the Boulder more neutral.
Marten Parker trio-Diamond Edition are incredibly good speakers use very detailed ceramic composite drivers Marten uses only premium quality parts throughout ,the $$ Jorma internal cabling,WBT connectors,high  Quality Mundorf Xover parts  special Diamond Tweeter ,and custom feet and damped cabinet ,several Excellent reviews out there on them.
and these beat  speakers of much higher cost .
@ronboco You'd be making a wise choice with the Rockport Avior ii's and the 866.  I own Rockport Altair 2's and would never let them go.  There's something very musical about speakers Andy Payor designs.  And Rockport's build quality is world-class. I use a Gryphon Antileon EVO stereo amp.

I recently purchased a Boulder 866 for a 2nd home system I was planning.  I temporarily hooked up the 866 to my Altairs and was pleasantly surprised on the musicality and level of control the 866 has on the pair of 15" side firing woofers in the Altair's. Not many amps are able to manage those woofers. Boulder is likely conservative in their power rating of the 866.  There's no harshness from the Be tweeter and the bass management is very close to the Gryphon Antileon EVO.  I suspect the 866 will mate very well with the Avior ii's. 

Check out the private message I sent you.

Good luck and enjoy the journey!
Retailers by definition sell the brands they carry.  The advantage is you can hear the combination.  The problem with this “hobby” is without the benefit of brick and mortar stores, we can go through this crazy ritual of flipping equipment just to find the right synergy.   My experience is that speaker/amp matching/optimization becomes more difficult they higher up the chain you go.  It’s took me 5 amps to find something that really made my YG Acoustic Carmels sing.   Took me 4 amps to find the same thing with my TAD CR-1s.   So I suggest go that is you like the sound of the Boulders with the Rockports, go for it…..   Hearing what yo hear beats all the opinions you’ll hear on this forum (an amp in hand is worth two opinions in the bush)
@co93 plus 1,000!

It never ceases to amaze me how many suggestions are offered when the person suggesting has not heard: the amp nor the speakers nor the amp/speakers with their recommendation for cables. Someone suggests cable A and they have no clue how it will interact with the amp. They suggest its the best speaker cable for speaker B when its the amp/speaker cable interaction that matters most.

Then....then there is the occasional dealer who chimes in after the OP has clearly stated that they ordered a Boulder 866 and Rockport speakers and offer up something like this: "I took a Whatchmacallit version 23 over to a customer's home the other day and he and his wife both loved it more than anything they've ever heard and they have a 7 year old cat". Oh the OP, stay your course, you heard what you heard and cables for the Boulder-Rockport combo won't be difficult or terribly expensive to sort. Also, the power supply in the 866 is so well designed and robust, you don't go crazy with a power cord...almost any wwell designed and decent cord will get the job done.