What you got from experimenting is different because you weren't space restricted and can still get proper airspace and port area with a slot. Now if you factor in the OP's space restrictions, you would easily know that round ports are the way to go. There's no argument over which is more efficient, its literally proven by math figuring out the total amount of surface area that air has to travel through, its literally what i meant by aero> octo > Slot, Just with round ports, you are stuck with the size given and doing multiples arent as efficient as a single big port so you are stuck with constraints. However when space is the constraint, there's no reason to lose .5 to a whole cube of airspace just to do a slot port.
It wasnt 6 months ago, it was a lot longer then that and that head unit did not have network mode. The current ones do.
You do know that bluetooth technology with 5.0 and aptx can stream high quality lossless nowadays right with? Literally no difference from a usb streaming lossless, both are digital forms of audio without any extra processing from the phone like it would from an aux setup.
