I'm a little confused by the context of the question but this may help:
ACPI is the most current spec used to allow a plug-and-play OS to handle all resource (memory, IRQ) assignments for devices as well as handle power management features like sleeping hard drives, displays, watching UPSs etc.
Disabling ACPI as a whole is a bad idea. You'll have to fool with resources, your computer will be incapable of actually powering itself off (ie "it is now safe to shut down your computer" messages) and other such problems.
However, if an OEM is giving you instructions for disabling ACPI for one particular device I would go with their suggestions.