WesM228, I have three JBL GTI 15" subs, two in a dual opposed box and one in a sealed box, I can say that you won't go wrong with them. My dual opposed box is the same size as yours. I sold my speakers and will be getting some new ones. Once they come in, hopefully in the next couple of weeks, I'll start a thread on my build since now I'm using a couple of "crappy" speakers and can't push the subs to the levels that I should. The little that I've heard at a low/moderate volume, I can say they are worth the money and then some. They are dynamic (pack a punch) and produce clean bass. I'll leave it at that for now, until further testing.
Out of the subs that you listed, I would take the JBL's. Don't let the logo on the dust cap bother you. These subs have a sophisticated motor technology (DDD) that will produce very low distortion and with their low Le of 1.0, you can cross them over at over 100hz if you have to since they'll extend high as the chart shows. I have two subs with the 5,000W logo on the dust cap which to me is so-so, and one with small white JBL letters in the dust cap which to me looks better. As for their "limited" xmax of only 20mm. If you have a big room, listen at reference or your priority is the low bass (below 30hz), use several of them. Ebay has them for less than $600 for two. I would wire these in parallel for a 6ohm load to the EP amp in bridge mode. Your amp does 2,000W at 4ohm in bridge mode, at 6ohm, the load will be a little easier on the amp and should still produce around around 1,500-1,600W which is "perfect" for two JBL's. Just my two cents.