@SidVicious (what a cool nick ;-))
I agree with the guy above. But you could also setup a spare "backup" Workbench disk for A500, and just delete some of the less important stuff on that disk, and then put the 6581sid.library on there. But make sure the disk still boots and functions okay :-) If you are using MagiC64 make sure its registered, i have the key file, which was given to me by the author via email.
Regards,