Can't decide on Integrated Amp - Please Help


Hi, really trying to find the best deal I can on a used integrated amp. My current set up is

Monitor Audio RX6 speakers
Oppo 105

Looking for a strong integrated that if I wish to upgrade my speakers will easily handle the change.

Looking at spending no more than $3,000 for a used example and would love some help. I stream most of my music through the Oppo instead of CD's and listen to a lot of Pink Floyd, Dave Matthews, Sting etc

Few choices i have outlined and really hard to be able to audition anything and would like it to match the speakers and Oppo well

Rega Elicit - R
Krell S550i
Hegel 200 or 300 if can afford (is the DAC much better than the 105)
Stello ai500
Saw a PLINIUS HAUTONGA Intergrated A but don't know too much about company.
Modwright 200

My room is around 15 x 15 with wood floors

Thanks in advance for help
simonmorty
Have you considered Pathos from Italy? It is both good sounding and stunning looking.
Some very good suggestions above, but recommendations would be much more targeted and meaningful if you told us what aspects of sound reproduction are most important to you and/or what you would like to improve upon.
Thanks for all the helpful advice and recommendations. Good question from Soix, I guess my current set up sounds pretty good to me for the money. Currently running through a Rotel rmb1075 as amp to Oppo directly. Guess looking for more of an open sound stage, detail, separation in hearing instruments etc. However wanting an amp that will last year's and power much more difficult speakers if needed. Although only wanting 2 channel still want it to sound good with movies also. In relation to type of sound, my brother years ago had a real nice Linn set up. Obviously Linn cost more once you start added pre/power amps but always loved the way it sounded. Not sure if this helps answer any questions? My concern with an amp like Rega/Nad is it won't be a significant step up. Was asked earlier by someone why not buy new, well reason is I can get more for my money used.
Also forgot to mention the amp must be able to connect directly to Oppo XLR so can utilize DAC.
I think you should check out the LSA brand of Amps(Statement). Also Ayon makes a tube Integrated The Triton earlier gens go for a lot better prices used. Both of these can drive your speakers no problem. LSA is a hybrid Tube/SS design, 150/300 watts 8/4 ohm. The Ayon Triton is a ALL tube design with 150 watts stereo. Also, the Oppo will allow use of Single ended cables so It dosent HAVE to be XLR. It will still be utilizing the ESS Saber dacs.