I am still waiting for my Nitro , but I have been seaching for aftermarket parts.$natch said:
Start with Mopar for some basic stuff. The other stuff is scattered all over just do a Google search. You may also want to try the other (blue Nitro forum) for more info.
No turbo or supercharger yet, no headers, no NOX. You can get exhaust from Gibson and Magaflow, a chip from Jet (for 3.7L) and a few air intakes.
No heads or cams that I have seen. The 3.7 is the same engine as used in the Jeep Liberty, so try searching Liberty parts also.