If you use Liberty headers you won't have a fitting to connect the EGR system. Nitros have an EGR valve (at least mine does). If you were to cut the header and weld a fitting on you'd probably be voiding any header warranty.
I inquired yesterday as to what parts the exhaust system might include. They stated that the only restrictive parts on the OEM system were the muffler and the tailpipe. They said it had an excellent "y" pipe.
In actuality who knows what they'll manufacture? I don't work for JBA, I just loaned them my Nitro for 3 days for the R&D. I inquired about exhaust systems from them back in January when I bought it. They called me last week in response to the e-mail, stating that they needed a vehicle to prototype with, and if I was still willing to loan mine.