I just happened to be going through the MGPRS2 FAQ myself. Maybe
this will help:
3.4 - Sound troubleshooting
3.4.1 - 3D Soundcards
MGPRS R1.05 contains a new version of the dll for the management of 3D
sounds (Wavd3BVR.dll).
If you still have problems, you can change in the Snd_cpa.ini file the
line Unconditionnal=None into Unconditionnal=WAVX2 or
Unconditionnal=WAVPW.
3.4.2 - Game crashes
If you have sound problems after patch R1.03 (or later) installation,
you can add the following line in the ubi.ini file into RS2 section:
SoundOptim=0
"But in a way, fear is a big part of racing, because if there was
nothing to be frightened of, and no limit, any fool could get into
a motor car and racing would not exist as a sport." -- Jim Clark