its cool man, everyone is here to learn.

ITR means, Integra Type R. the stock integra type r exhaust is 2.25inch piping, which would flow better than a stock ls exhaust and wouldnt have any noise.

will it flow better than aftermarket exhaust?? dont really know, but i would believe that the aftermarket exhaust would flow better cuz of the design of the piping and the straight thru design of the mufflers.

right now im running a T1R(Type One Racing) bpipe which is 2.5inch piping going to the stock ITR axleback. flows pretty good and no exhaust noise.