I'll be getting some more subs today.. 3 JL W610's in a box.. I already have a JL W315D4... I'd like to set something up with all 4 subs, but I've heard from others a few theories, such as different sized subs of different ratings don't sound right together, etc. Can anyone correct me or agree? I figured if they are setup right on different amps or something, it shouldn't be an issue.