Do I need upgraded power cables?

I would encourage you to borrow the Acoustic Zen Satori cables and Matrix Ref. II Interconnects for reference if nothing else.  If you can find cheaper cables that can match those then you’ve really got something.  Best of luck in your search. 

@stuartk  I ran two lines and it was like $200 plus cost of the outlets I bought, but my walls were down at the time so may be more if they have to snake the wires and cut holes.  Just to give you a rough idea. 

I’m looking into the acoustic zens. Just wondering why you suggested them. And if you don’t mind - what do you think about about Cardas Persecs?

Thanks @mclinnguy.  I recommended them because you think the Kimbers are bright sounding and the AZs are not, and if they don’t work out you can turn around and sell them for little/no loss so very low risk to try. They walk that rare line of being nicely detailed in the treble but in a very refined way such that they don’t sound bright nor rolled off, and they offer excellent tonality, imaging, and 3D soundstage. If I were to sum them up I’d call them effortlessly natural sounding where nothing stands out. I’ve been using them in my system for about 20 years and they have held off all comers at or near their price, and I have recommended them to several people here over the years and all have been very happy/impressed with their performance. I don’t know anything about the Parsecs and couldn’t find any reputable reviews of them so unfortunately have no useful info there. In the past the more entry level Cardas offerings have tended to be on the warm side with a polite treble balance that I found to be rolled off with the ones I tried years ago (Ultralink or Quadlink I think — can’t remember), but I have no idea if the Parsecs have that quality or not.  All I know is that the AZ cables/interconnects are all-around excellent performers and an outstanding value especially when buying used. Read some reviews for more perspectives, and hope this helps.

I’m pretty confident these will bring significant improvements over what you’ve had to date. 

https://www.usaudiomart.com/details/650192681-acoustic-zen-satori-speaker-cables-25m/

https://www.usaudiomart.com/details/650192584-acoustic-zen-zero-crystal-matrix-reference-ii-10m-and-15m-rca-and-balanced-11-pairs/

I've had the Kimber 8ts and Silver Streak about a month and things are sounding too bright.

What cables/interconnects were you using before?  I’d wait til you have at least 150 hours of playing time on the Kimbers before making any firm conclusions, but it sounds like they could be a mismatch for your system.  Your speakers are known to lean toward the bright side so cable matching becomes even more important, and if it’s still too bright after 150 hours it’s time to move on to something else.  I have recommendations for some very good used cables you could try that’d likely make a big improvement both in brightness and imaging/soundstage for not much $$$ if you’re interested and the Kimbers don’t work out. 

You mentioned Pine Tree Audio - what do you think of their Iso-Power 15A Power Filter?

Sorry, forgot to answer this.  I’d wait until you can buy a better conditioner like the Core Power I linked above that will likely make a more significant difference.  Another option, and what I did, was to wait til a used Audience AR1p conditioner becomes available that you should be able to get for about $200 and then plug this power strip that’s very highly regarded into it that will give you nine outlets.  So for around $335 you’ll have a very good conditioner on the cheap for all your components.  

https://us.rs-online.com/view/search?keyword=Wiremold%20L10320

But I would still give Pine Tree Audio a call because they’re apparently very helpful if you tell them what you’re looking for, and you may be able to try some PCs on the cheap just to get started replacing those awful stock cords and see if they make a meaningful difference. 

There are times though (especially in dense musical passages) that the sound is stage is a blur - as if of all the instruments are coming from the same place.

A good power conditioner can sometimes help individual images pop by reducing noise.  Here’s an EQUI=CORE 1000 if still available you could probably get for $600 I’d think. 
https://www.usaudiomart.com/details/650092255-core-power-tech-equicore-1000/

Also, how are your speakers positioned relative to the back and side walls, how far apart, how much toe in?  Speaker positioning can also be a big factor in improving imaging and soundstage.

The Panamax certainly isn’t doing you any favors. I’d replace that first with a good conditioner as that would benefit all your components at once and then address individual power cords when you can after that. The EQUI=CORE 1000 offers balanced power at an attractive price and worth a look.

https://www.underwoodhifi.com/products/equicore

Both Ice Age Audio and Pine Tree Audio offer high value power cables if you want to explore those. Hope this helps, and best of luck.