I have a custom fuel injection project. Rather than place the electronics under the hood, I intend to have the ECU mounted inside the vehicle. This brings up some questions. First, is a sealed connector necessary for interior use? I'm on the fence on this since the interior is a somewhat protected space, but reliability is an issue here. The second question is the use of tin plated contacts. I have seen a number of examples of automotive contacts using tin, but I've also seen warnings about tin doing bad things when exposed to the temperature and humidity swings typical in a vehicle.
I'm tempted to just eat the cost of sealed connectors with gold-plated pins. But these add significantly to the cost of the project and it's not clear if it's worth it. Opinions?