If you have an older player then you can apply the principle "the slower the better". But who expected players to read CD-RW (recorded as audio) or MP3, or that players would have an anti-shock buffer? So in the new players you won't have any problems if you record even at 52x speed. However, it all depends on what you want to play it in. Sometimes recording at 4x speed can only be a waste of time, because many players have drives that are as efficient as computer drives (though maybe I exaggerated a bit here).
It also depends on how you make the CD, whether you use OverBurning, or whether you don't end the session. You need to know what you can afford on your player.
As for audiophiles: what has gingerbread for a windmill. All data on the CD is in digital form. If he wants to have good quality on the disc, recording as slowly as possible, let him record a vinyl disc, because speed matters there

. The most important for me (and I consider myself an audiophile) is the quality of the playback drive and the playback system (Hi-Fi).