Hi Soix,
Looks like you are an experienced one. Yes, I am using Iris with the Pontus. With Bluesound, the sound does feel less grainy too. Also I experienced that with intranet cable, (got a good quality one from Alliexpress for better than eBay price) the sound does not some worse than WiFi sound for sure. Also, I noticed almost none short sound drop outs or interrupts. Also never heard any occasional distortion when the volume is high. I think there are reasons why Bluesound asked you to use intranet as much as possible. I am glad that the intranet wire, a thick, not flexible orange wire, can give me a better streaming experience. For the linear power supply matter, I understand and believe that it will improve the sound. I have my headphone amp and Foci basic D amp as examples. However, I do not know how to implement it on Bluesound Note. I did buy an Audioquest power cable to power it and heard less noisy background. I have every unit powered with a good power cable. I feel confidently that power cable makes difference. But I do think that do not spend on power cable more than on the components. My recent upgrade from Classe CP 47.5 to CP 50 showed that the component is the first factor to improve sounds. Any one need CP 35, 47.5 and 50 and SSP 800, I can share with them.