It is counter productive to be aggressive towards someone who doesn't like risk.
My smartphone has official custom ROMs and official Root and official unlocked bootloader. I have none of those at the moment since I'm pretty good with the performance so far
For X5-3, on the other hand, I would consider something interesting to strip off all the software modules that I do not use. Say, BT module, certain apps and such.
I really need a very minimal DAP with a great sound - I actually dislike my DAP being able to do too much.
To explain why, consider this: I have a 6.4 smartphone. Any inernet / video / anything visual or games will take place on that phone.
I have a computer.
I only need a DAP to listen to music, and that is it. Maybe to show the cover art since I consider cover art to be a part of music, but nothing more. I want to strip off everything I do not use to gain more battery life and such.
As for the differences in sound, as much as I like the idea of custom ROMs, I don't have an X5-3 to test so I cannot say. In theory, any gains in sound would need a logical explanation