Have you seen these rather slick new gauges for the Toyota GT86?
The idea here is that the clever P3 system can be slyly installed into the heater vent, so you get all the functionality of a proper OBD2 data scanner, but with a stealthy OEM look.
The system is designed to display all the essentials like, oil temp, air-fuel ratio, coolant temp, intake air temp and all sorts of other gubbins. It can also be used to delete fault codes, and even has a 0-60 timer.
The best thing about it though, is that there’s absolutely no messing about to get it up and running. The whole system is totally plug and play, so you simply whack the plug into OBD2 port and away you go. Magic.
For more info see P3 Gauges