audison bit one, jbl ms8, arc audio ps8, helix dsp/dsp pro, rockford 3sixty.3 all are superior offering 8 channels of bandpass capable tuneability with 31 bands of EQ. vs that sony's puny 10 band and 6 channels of output. All you need is a reciever that handles FLAC and you are fine.
I've been to a few SQ competitions where there were several people like you who think flac is everything and they got beaten bad by people streaming bluetooth with spotify premium which is only 320kbps or itunes which is 256kbps(what the 1st place winner used for demos and he indeed sounded THE BEST). The reason why they lost is because the people who won used their money way better and had proper car audio knowledge with a much superior install vs the transitioning home audio/head fi audio person that has ZERO grasp of what car audio sound quality truely entails. PS the spotify guy had much MUCH cheaper equipment than the other guys. He placed 3rd in a group of 16 people while the others got dead almost dead last, grouped in with the SPL guys that are trying to do sound quality.
So NO that comment is FALSE and proven FALSE at competitions where the pros compete at. You just need to be past a certain threshold, afterwards its SEVERE diminishing returns. Money could have been spent on BETTER quality drivers and a BETTER install/tune instead.
Your initial post about using coaxials is VERY concerning because very few, if any person in their right minds use coaxials anymore for true sound quality.