NAD C 658 is a streaming DAC that is getting some great press. Plus BluOS is more than able to satisfy an audiophiles need and it is modular so that helps to put it above the fray. Now if you have big bucks go Linn Majik entry level ($4,000), and never look back. This offering is one hell of a feature rich streamer that beats out auralic at least in my humble opinion.. And if you are fortunate enough to be loaded for bear there are the Hifi Rose 150 @ $5,000 or the more affordable 250 model @$2,500 i think.

On the Plus side of things to consider:                            Linn has an option for an upgradable power supply too i believe but the Rose150 also has the ability to add there CD Player-Ripper ($400 very specialized) and the 8-14" screen that plays 4K movies and acts as the menu is also easy to operate. I know this because i read about their history. The company started out making the touch screens used on  airport ticket kiosks for years.  So, enter Hifi Rose and the lovely screens were an easy adaptation. And, since it was always being improved upon while they were servicing the airport travelers need for tickets it was improved upon before adapting it to the HiFi Rose so it is top notch now i bet. So the NAD C268, Linn Majik, & Hifi Rose 250/150 are my top performers i would send to the audition.      

+1 @glennewdick reference upgrading the DAC, also you can upgrade the node with an outboard linear power supply. This will really elevate your streamer. 

C658 had too much under the hood ! Just ditched my NAD C658 after a week of ownership being it was so buggy requiring numerous factory resets to unfreeze the unit. Heck, spent more time fussing with the thing than listening. Until the Mfg’s stop trying to be more profitable by jamming all this stuff in to one chassis with the barest of power supply’s with app’s they expect you to be their beta tester on, these “all-in-ones” are just going to be commodity / mass market items fighting for retail space on the shelves of Best Buy and the likes..

Tfeldhaus,

No experience with your current equipment, but the following is working really well for me.

Network switch - Supra Cat-8 Ethernet cable - Bluesound Node (latest 130 version) - Supra Excalibur USB cable - Denafrips Iris DDC - Audioquest Vodka HDMI for I2S - Denafrips Pontus II DAC

The answer to your question is No you will not get better sound quality putting a $3k reclocker on a $500 streamer.