Sampling one side is good for both sides. The 03 with only one O2s doesn't need to sample both sides. 04 and above uses two probably to better meet emissions. Of course the extreme going the other way is to have a sensor on each cylinder which the Megasquirt can support. Trust me it is how all LT's are setup on 03's.I got that part. Lol. But just having a hard time why u would install it on the driver side where it only reads that side and not a mix from both sides of the engine.