Kinki studio EX-M1, EX-M1+ differences... vs Denafrips Hestia/ Hyperion combo?


I've been reading up on some Integrated Amps and Pre-Amp/Amp combos lately but have some questions.

The following is an excerpt from SoundStageHifi:
The original EX-M1 was introduced in 2017. The newly updated EX-M1 — without the “+” — costs $2398 and includes, among other things, changes in the power supply, capacitance, and the volume control, the latter now using a MUSES72320 controller instead of the previous relay-based control. The EX-M1+ is essentially identical to the upgraded EX-M1, but adds a preamp-stage output and a home-theater bypass to entirely bypass the preamp stage.

That last sentence has me a little confused. 
"The EX-M1+ is essentially identical to the upgraded EX-M1" - What is the "upgraded" EX-M1?  Does this mean that the latest version of the EX-M1 has all the updates that they just covered preceding this statement?

The 2nd half of the statement says " but adds a preamp-stage output and a home-theater bypass to entirely bypass the preamp stage." - You'll have to excuse my ignorance.  Does this mean that I can add a pre-amp in the future and use the EX-M1+ as a Power Amp?  Also, does this mean that I cannot add a pre-amp to the EX-M1 (non-plus)?

At this time, I don't have hard to drive speakers, and I don't foresee having something like that anytime soon, so I was also considering the Denafrips Hestia/Hyperion combo.  I haven't seen any reviews comparing these 2 company's offerings... any feedback is appreciated.

jwlaudio
@jwlaudio that's great I've heard First Watt amps a few times at shows always sounding great you basically can't go wrong with a Nelson Pass amp. And a tube pre and great SS amp is a fantastic combo for many listeners. And yes those class A amps do need extra ventilation get it away from that thermostat lol!
@jwlaudio 

Just a bit of info that may or may not be important to you from an owner of the BHK preamplifier for over three years.  As the F8 is a single ended amp and the BHK is fully balanced you are likely to run into two small issues.  One is you are likely going to half to lift the ground on either the amp or the preamp and secondly the BHK preamps in general are not fond of SE amp connections as it tends to cause an increased level of clicking with their unusual volume control.  I tried mine with well over a half dozen SE amps and the increased clicking occurred with each one.  A friend tried two different samples of the BHK and ran into the same issues and this includes SE amps with convenience XLR connectors.  Another issue that may limit your tube choices is that the BHK needs input tube with matched triodes to keep the volume control noise in check which is much harder and more expensive to find in NOS variants than in new production tubes.  But in the end if you have an amp that the BHK "likes" then it is a very solid choice.  
@jackd 
Thank you for the info. What does "lift the ground up" mean? I've read about all the quirks of this preamp, but it seemed to be a trade off people were willing to deal with because it improved their sound.

I was looking into the Decware zbit to increase the voltage to my F8 because right now with the DAC controlling the volume, I can max it out and it's loud, but nothing too crazy.  I'm just not used to having my volume at 75 to 90% all the time.

I don't plan on tube rolling any time soon, so I'll have to cross that bridge when the time comes.

Like you mentioned, since the F8 is SE, I've wondered if it's worth connecting everything else with XLR.  

What amp have you matched the BHK Pre with?  Do you have an experience with mating it to the BHK 250?
@jwlaudio

By lifting the ground I mean using a cheater plug preferably on the preamp and if you are plugging into a grounded conditioner it won’t make a difference anyway.

In the 3+ years I owned the BHK I tried it with the following amps all from memory. Mystere PA-11, Music Reference RM-10, Granite Audio 861 mono’s, Nuforce STA-200, Nord One, Nuprime ST-10, Mivera Purepower, Odyssey Kismet, Kinki EX-M7 and the BHK 250. The best match was obviously the BHK which I still have and swap in and out with the EX-M7.

Sticking with the stock tubes or the Gold Lions is a good place to stay as finding NOS as quiet will be hard and expensive in most cases. When you get the preamp I would suggest you take the tubes out and re-seat them after their ride with FedEx.

As to the cables for a start use what you have especially if you don't have a long distance to run or noise issues.  
@jackd

I take it "lifting the ground" removes noise?  Worst case I can just return the BHK Pre, or sell the F8 and buy the BHK 250, I guess.... hopefully I don't run into too many quirks.

Thanks for this info, I know what to expect.