This is for a 325iS destined for Spec E30 but I've lurked here on and off and I think you guys have enough experience to point me in the right direction.

Where do you buy all of your sensors from? I need oil pressure, oil temp, water temp senders, etc. I'm planning on monitoring oil pressure and temperature and water pressure and temperature.

I want to route the output from the sensors into a microcontroller (Arduino Uno) and then write a simple code that will dump the information onto an LCD screen as well as sending the data to a SD card for datalogging purposes. I don't think I want a ton of gauges all over the car since I'm never going to have time to look at them.