The a/f gauge is going to be useless. Also installing the a/f gauge and the egt gauge is redundant. Both gauges are used to tell you the same thing; are you running rich, lean, or stoich. The a/f gauge is pointless on an OBD II car as all it will be is eye candy. The most this gauge will tell you is your o2 sensor is working. The EGT gauge, unless you're running Turbo is almost pointless in a naturally aspirated car. The gauges I would recommend would be: oil temp., oil press., water temp., and fuel press. If you insist on installing the EGT gauge, I would recommend tapping into the #4 exhuaust outlet on your header as this cylinder is the farthest from the inlet of the fuel rail and would most likely be the most lean cylinder. You could also weld a bung to the mid pipe right after the header collector. Good luck.