Hi Jared, welcome to the forum. Both things work well with the 318, a good strong engine overall, neglected on its capability really. Being the intake valves are small in the 318, headers really don't show much improvement on a street engine with the small valves, but dual exhaust will help, add a cross pipe near the rear of the transmission (location-wise) to balance the two sides. The 318 also likes a performance 340 cam, something in the .435-.450 lift range and a duration in the 260-265 range. This will keep the bottom end but still allow it to breathe better than the small stock cams, and still keep from killing gas mileage. Going too big with a 318 is kind of a no-no, since there was never a performance evolution with the 318, they usually have lower compression so unless you do a full teardown, install larger intake valves and a higher compression flat topped piston, the above items/recommendations will still eek out a little more power without compromising its drivability.