To power condition or not

I think you have answered your own question, why don't you try both options and use your ears to tell you what's best. I envy you as I had the passive 40s a few years ago and loved them so much I bought a pair of active 100s to replace them . ATC make fabulous speakers especially if you like your music at real levels.

Try both. I have never had a problem with ATC Actives - dead quiet even with your ear right over the tweeter. It is crucial that you use XLR - a good cable in Canare Star Quad. If you use inferior RCA and adapt that to XLR adaptor then you can of course expect a much higher noise floor.

Whatever way you choose to go, get a couple Perfect Path Technologies E Mats to put on the inside of your electrical service door.  They will improve the sound of everything in your audio system as well as your video and all things electrical in your home.  They are the type of thing that once you have them and hear and see the improvements they yield you won't be able to do without them!

Depends on the total draw of all your devices and the capacity of your household circuit and that of your Furman, which is matched for a 15A circuit.  The Furman manual states a 1300-1700W work capability---about the same as a 15A circuit free of other devices and appliances.  It may be best to limit the demands on your Furman to either the amps in your new speakers or to your other amp or amps, but not both.  Have to favor your front-end devices overall with a mid-size power-on-demand conditioner on a 15A circuit, if that is what you have at the wall.  Could try it all via the Furman at low volume--then try higher.    

Shadorne,

Will have high quality RCA to XLR cables made, no adaptors.  German manufacturer or Analysis Plus expected.

There are dozens of threads on this subject check them out.

They should be fine thru the Furman. They’re efficient speakers and other component minuscule. You’ll probably never draw 6 amps peak !

Power conditioners will only clean the power if it’s dirty. Have a licensed electrician do a power quality test and you’ll know how good (or bad) your power is. Regardless, a panel mounted TVSS is money well spent, as are decent quality TVSS-equipped power distribution units between the receptacles and equipment. If you are in need of brownout and blackout protection as well, don’t waste your money on a low-end UPS that puts out square wave power. Pony up the money for an online double-conversion UPS with true sine wave output. I use Eaton 9130 UPSs, which are commercial data center grade, but they have noisy cooling fans, so they’re located in the basement so my listening room is as quiet as a library. 

The Windows that you're using is very important to know whether you plug it directly or not.