My Magnaflows (street series and competition) have drain holes on the bottom about 3/4 of an inch from the end. I have read you do have to drill water drain holes on some axle backs but i don't know which ones
I must add: Drain holes won't do anything to the sound.
Little Red. 2011 V6. Automatic Trans., C&L CAI, JLT Catch Can, BBK Ceramic Coated Long Tube Headers with BBK Catted X Pipe, Axle Exchange (American Muscle) Aluminum DriveShaft, GT 500 Lower Control Arms, Koni (orange) Dampers, Steeda Watts Link, Ford Racing 3.73 Gears, Magnaflow Street Series Axle Backs and a few more mods....Wifes car, 2014 Ford Edge Limited.