Responses from testpilot

Typical lifespan for a 5 channel power amp?
With multi channel HT amplifiers the technology becomes obsolete before the operational lifespan.  
Narrowed it down to two Monitors, Dyn Heritage Special, or Wilson Tune Tot
You must do yourself a favour and listen to the Dynaudio Heritage Special.  Outstanding speaker.  Sorry, no experience with the Tune Dot.  
All things being equal (hypothetical) which do you prefer, XLR or RCA?
In most posts, people are describing their preference between a dual differential balanced circuit and a single end circuit. If you compare a xlr cable with pin 1 and 3 tied together with a rca cable of the same make in a single ended circuit, the... 
Speakers The single most critical component
When I read the OP’s user name, I was expecting a different writing style.  In any event, speakers are just as important as the the rest of the components.  
EXTRA! EXTRA!! Millercarbon Proven Wrong!!! Read all about it! EXTRA! EXTRA!!
Where can one try out the “Heisenberg” power cable? 
Which pre amp do I keep, Perraux SM-2 or Plinius CD Lad
Not sure why you asking for opinions when you own both preamps under consideration?  Keep the one that sound the best. 
Equi=Core 1800
Underwood Hifi has purchased the assets of of Core Power Technologies. The new name is Core Power Technologies A/V.https://www.underwoodhifi.com/products/core-power-technologies-av 
Linn Karousel bearing
I would trust @daveyf’s advice, he knows Linn tables. 
Japanese Audio
Low powered amplifiers were born out of necessity as the average sized living space in Japan is less than 1,300 sq ft.   
All things being equal (hypothetical) which do you prefer, XLR or RCA?
Not so hypothetical as some companies offer both rca and xlr connections on single ended only equipment for purely convenience sake. In these situations, I prefer xlr for their more secure connection and strain relief.  
Scams in the audio industry?
To quiet the naysayers all a company needs to do is offer either a trial period or a money back no questions asked guarantee. Companies can either talk the talk or walk the talk, I’ll deal with the latter.  
Absolute Phasing
It doesn’t matter because the sub’s driver is not on the same plane as the main speakers, therefore, the phase alignment is already off due to physical placement. This is one of the reasons that a lot of higher quality subs have the ability to adj... 
The myth of "best" in audio needs to be addressed by all of us
There is no universal best.....just a best for you.   
Are there passive attenuators that don't zero volume and only offer one input ?
@dbxrecords ....why not just disclose or post under your industry affiliation? 
good looking speaker stands
Check out Solidsteel speaker stands  https://solidsteel.it/my-product/ss-5-vintage-hi-fi-speaker-stands/