I have two of them as well. Mine came with the stock sunn/eminence 60 WRMS speaker of the day, but I'm sure the upgraded versions were available with JBL D-140's. I've reloaded mine with a JBL D-140 in one cabinet and a 300 WRMS Eminence in another. I use them with a sunn concert bass head. When using only one cab I use the Eminence (I've blown the JBL before, but they sound great right before they blow), and I stack with the JBL on top. The two speakers do sound "different", and the blend is quite good though it would be hard to say which one is "better". If you ever decide to off your rig, let me know. Great overall cabinet design. Useful for practice, gigs and recording.