hmmm, actually im not sure it if would make any difference at all, mabye 1 db lol, not worth the argument, but i would personally say no, becuase i would never put my subs in danger of what you would be doing push pulling
Isobaric (push-pull) is equivalent to a sealed sub with twice the motor strength, and the same SPL as a single sealed sub, making it less efficient since you're doubling the power It is the same SPL as a single sealed sub, the only use for them is to use a smaller enclosure volume. So no, it won't be as loud as two sealed subs, actually it'll be nearly 6db down.