This is one of my main gripes with GT5. Why oh why oh why oh why can you not change the menu music? The menu music is so awful it has got to be delibirate. I will admire anyone who can tolerate the ear assaulting Japanese nonsense for more than 10 seconds.
Surely the menu music is more important than the in game or replay music? I would imagine most people would turn in game and replay music off surely
You can change which of the 'pre-loaded' songs (the ones that come with the game) plays during races, menus and slideshows (photo mode).
From your GT Life screen, in the bottom left of the screen is a 'Music Library' icon. If you select that it brings up all of the songs included with the game (all 189 of them). You can then select each one individually and select whether or not it plays during the race, over the menus, during slideshows (or any combination of those 3) by pressing triangle once you have the track selected.
No more bizarre Japanese piano jazz for me! 👍
On a side note, it's amazing how they've picked so many crap songs...