I just installed the PLX AFR and highly recommend it. Mounting it was extremely easy without cutting up the dash, as its about a 1/2 inch thick. Here's why I love it:
1) It also tells you the battery voltage. Huge perk!!! With a press of a button it becomes a battery meter with graphing. Helps tremendously with racking down 911 battery/charging/electrical issues.
2) It plots out the AFR on the screen. So, you can glance down and see what the last 10 seconds were like. Extremely useful.
3) The unit simulates your o2 sensor output. What that means is you just need 1 o2 bung hole, and 1 o2 sensor. This feeds the unit, and then the unit feeds the cars CPU. Works great. Beats mounting another bung hole.
3) The best feature is easy mountability. Here is what I did. I ran the wires from the o2 sensor through the tunnel, and put the main unit under the seat. Then, I mounted the guage just to the right of the steering wheel. On your car there is a little vent hole there, its the size of a nickel. It is easly pulled out. I took this little vent plug out, and epoxied the guage to the back of it, with the wire running through the hole. Mounting the guage just requires pushing the guage with the plug on it, back into the hole. VIOLA!!! Works perfectly, no dash damage, easily reversible. And better yet, you can easily see it while driving. You can't do that with any other monitor.
I haven't seen anyone else do this, not sure why. Its a fabulous way to mount it!!!
PLX DM-6 SM-AFR | Wideband Air Fuel Gauge
<$200 on the net if you search for it!!!
Highly recomended.
Bo