it's kinda sad that some guitars wren't made to accomodate EMGs, coz if we have to dig a hole in 'em it's gonna upset the tone...
but IMO it's better to have a specialized cavity for the battery. i have a friend here who installed EMGs into his BC Rich Warlock; he has to tape his battery down, it's kinda awful...

everytime the tape's adhesives wear out, u can hear the battery dangling & knocking against his guitar. sheesh. :lame:
but that EMG crunch is kinda irresistable...