I'm with PHiZ. If you want A/F, get an APEXi turbo timer. It's 10X as useful as a A/F gauge and happens to have a o2 meter, A/F ratio, and a voltmeter built in as well. So for the third gauge, get a clock Otherwise, get a 2-gauge a-pillar. 3 gauges will obstruct your view, in fact I hate my a-pillar mount. You can get fuel pressure and oil pressure in a bezel-mount.