Platform Advice Request: Porsche 968 OBD-I Multi-Function Gauge (PDuino)

I'm humbly seeking the collective's platform advice for my first (arguably complex) Arduino project. The intent is to monitor systems not available by default on older Porsche platforms (which are OBD-I) and display the results in an embedded display inside the gauge cluster, a la more modern cars. Projects using the more modern OBD-II system are not entirely useful as the protocols are different, but they may provide help on the sender-side (e.g. how to read boost, temps, etc.)

After doing some research, I've settled initially on the Arduino Uno R3 and the 4D Systems' uOLED platform, with input collected from a joystick or multiple buttons.

Above all, it must look professional and it must be "automotive grade". I can't put hobbyist-level equipment into the dash of the car, or have a fragile joystick sticking out of the dash.

The interface work is progressing, as seen below, but before I get too far, I wanted to see if the forum members might have some great "watch out" advice, or even advice to switch to Raspberry Pi or something more powerful?

Thank you very much for any advice.