A problem with 60 fps PAL code

[gtgamer468]

I enabled a cheat for Gran Turismo 4 Prologue PAL version where the speed can be lifted to 60 fps from the normal 50 fps. It works just fine, but the menus are getting slightly too fast, gargling the menu music. Is there a way I could try to slow down the speed in the menu and speed it back up in the pre-race menu, perhaps with the framelimiter in GS settings under emulation?