Coils, Suspension, magnet slug quality, gap size, etc... all can be drastically different and basket, back plate, cone, and surroudn can be identical. The two woofers will sound drastically different. As far as a head on comparison. Loyd is doing one and I'd like to do one. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif