Ok, here's the deal:

I recently installed Grom VAGTU3 for added functionality, mainly playing music from my phone and through its USB-port from a memory stick. I also bought an interface cable to use the OEM USB memory stick functionality (MM-toggle in CD button).

Now everything "works" but not quite how I'd like. Grom doesn't display song titles at all, just "Track 1" all the way to 99 so choosing songs is a hit and miss proposition. That might be a feature and not a bug, though. MM does display them but only after you've played the song and the whole list is empty every time when you start the car. Which makes choosing songs you haven't already played impossible unless you just skip to the next track and hope one of them is eventually something you'd like to listen.

Am I doing something wrong here, ie. is there a set file and directory structure for the MM, or would creating a m3u/m4u playlists on computer of the contents of the stick help?

If not, let's move on to the next step: as I have Naim audio in my car, what - if any - functionality would I lose if I upgraded the head unit to something else? Either Ben Hur or one of the numerous chinese large touchscreen units.

I really hate not being able to choose the exact music I want to listen or even Grom not displaying titles properly. Using my phone for music is out of the question, BT is there for my kids and I can't be bothered. Something needs to be done. Getting all songs displayed by MM (or Grom) would be ideal and all I really need but if that's not going to happen, I have to find another solution.