You can not replace the ‘head unit’ so as you seem to have the all the things that work in your other car then why not just try them in the 5. You can not damage it so just go ahead and try the things that you are interested in.
You can certainly use both USB slots but not at the same time, you have to chose ‘a’ or ‘b’.
You can use usb sticks greater than 32gb as long as they are formatted to Fat32. Mine doesn’t get confused by track numbers but I download whole albums. Artwork is done by Gracenote as far as I can tell.
Also worth considering updating the infotainment system to the latest and final release. Pm me for details.
Will the Mazda radio support bigger USB drives using the exFat file system - or am I stuck with a 32Gb on FAT32? Yes, it will support bigger, I have a 64GB drive in mine without issue
Is the ND sensitve about metadata? In my other cars running the MP3 files through MP3Tag seems to rectify most issues. No, not that I have found, but I do try to clean my files up so the correct data etc. comes through on the display
Any issues with album artwork - maximum size / resolution? No, not that I have encountered anyway
Does it get confused by track numbers / disc numbers? No, seems to be pretty happy with disc and track numbers, reads most metadata but I do have some memory of adding disc/track numbers to the front of the file name so it might not be perfect
Can I use 2 USB memory sticks - one in each USB? Yes, they are two separate inputs so you can select either to play from as you would FM/AM/etc.
