I wondered if it would be possible to revert the sound drivers back to 10.1.x, and searched around the /System -> Library -> Extensions folder and found a file named AppleOnboardAudio.kext.
I figured if I replaced the kernel extension with the previous version, things should be back to normal. I used Pacifist to extract the AppleOnboardAudio.kext from the 10.1.3 update package and used the Terminal to replace the newer version (I'd keep a backup, just incase). After a reboot all audio was exactly as it had been before Jaguar.
I've heard quite a few complaints from others about sound quality in Jag-wire, so if you're one of them, here's your fix.
[Editor's note: Clearly this hint falls in the Highly Experimental category! I have no idea of the possible downsides of running an older audio extension with the current system ... so if you try this, please proceed with caution - backup early and backup often!]

