Balanced vs RCA between amp/preamp

Actually the performance "hit" is when you pay more for balanced and get less for your money than RCA. Balanced is one of those things that makes a lot of sense for professional use running long distances and lots of connections giving the locking feature value. None of which applies to home use.

Absolute polarity is another non-issue. And even if it does make a difference the only way to know for sure is to try both ways and listen. Don't be surprised if you hear a difference. Also don't be surprised if you then discover it sounds better one way on some recordings, and the other way on others, and with the total barely noticeable if at all difference being in no way worth the hassle of switching. Which is why its a non-issue.

Good point Millercarbon 

one other thing to consider is the Marantz actually true balanced or just single ended looking as balanced. True balanced is a lot harder to do and can give benefits in cable cost and ability to run longer runs. true balanced negates many of the issues with cables and EMI as the balanced signal cancel out the EMI more then single ended can.  In theory you don't need to spend huge money on balanced cables as they require less shielding. 

I'm sure someone here with more background in balanced systems can inject more information and details as to the benefits losses.

Balanced gives you better electrical noise rejection (if you need it), but costs more and requires additional circuitry to make it  (less is more).   I don't have a choice since my current and previous amps have only XLR inputs, but I still appreciate locking feature.  In addition to locking XLR has only female end exposed - in case something gets disconnected.  It is additional protection from touching "live" wire.  

I've read plenty of reviews and checked the Marantz site and cannot confirm either unit is fully balanced or just has the balanced connections so no help there.

I agree with Millercarbon that listening is the proof. Thanks for your input gentlemen.

Any other input is welcome......

Read third post down from KBK...great explanation.  

https://www.stereophile.com/content/balanced-xlr-vs-unbalanced-rca-1

The fact that the Marantz units and your sources are not fully balanced means you will likely experience minimal gains vs. single ended connections.  in fact, there are occasion where you will find the single ended connections may sound better.  I can't speak about those explicit units, bit I have an amp where the single ended connections definitely are better than the balanced.