You said "Dual exhaust system" a lot. :silly:
Anyway, there are a few rears that you can go with a dual exhaust system. The Blitz, Bomex, Invader 6, fiberglass
Kaminari(Not the Urethane), Trial, and Extremor. Those are the popular bodykits, but there are others out there that you can put dual exhaust on.
View pix of each here.. https://www.celicahobby.com/gallery/index.html