I own the Paradox #5 so hearing you say the JH13 is inferior baffles me a bit; I was planning on getting the JH13 freqphase.
I mean, the T50RP Paradox is fantastic, but I'd compare it to headphones hovering around the 500$ range at most. Overall I'd put it between the HE400 and HE500, but both those headphones have it beat on pure resolution because of the superior drivers. However, the decay and linearity of the Paradox is incredible as that was the main point of the mod; making it a reference/monitoring headphone (as far as I'm concerned).
I'm listening to them right now as we speak as my curiosity was piqued; kind of really underwhelming after coming off a NAD m51>MC225>HD800 rig lol