If you were to combine the two 2-1 pipes, then you would basically have a really long 4-2-1 exhaust. if you plan on running 2 completely seperate exhaust pipes. drop the diameter down to 1.5" That is still the equavilant of a 3" exhaust for all 4 cylinders. You would lose a hell of a lot of low down torque, but gain on the top end. You would also need 2 cats, one per side, plus 4 o2 sensors, and something to read the 4 o2 sensor signals and make sense of the readings for the ECU.... You would also add a heck of a lot of weight for what would basically equal a wash performance wise...
Leave it to Random to Needlessly complicate things.
Leave it to Random to Needlessly complicate things.