I never really thought about it in monetary terms but I guess I would have to say no, it isn't worth a $600 difference. I can't imagine you not being satisfied with the 2245H's.
But then again, dual woofers are a very big selling point in certain parts of the world...
I personally don't do aftermarket kits in JBL cores so this information is meaningless to me. To me it is completely pointless to put non-JBL software into JBL hardware. Buy a Radio Shack driver instead, they're cheaper to eff around with.