This is by far our most asked question. So how do you know what unit is in your E30? Well, here are a couple of ways you can tell.
Your E30 3 series or M3 will have the either "VDO" or "Motometer" stamped in the gauge cluster between the RPM and speedometer. This is not always correct. We can say it is about 70% of the time. Some VDO units ended up coming with Motometer gears and vice versa. This can only give you an idea.
This is the most accurate way. It is best to take your steering wheel off using a 7/8in or 21mm socket. Be sure to be careful with the cluster's "V" shaped tabs when removing as they are easy to break!
Once you've removed your cluster, you will notice stickers on the back of the cluster either saying "Motometer" or "VDO".
As you open up the cluster, you can make absolutely sure by looking at the actual gears or the circuit board . Pictures below:
Be sure to pick out the correct odometer gear set for your vehicle. Odometer gear teeth counts differ based on Euro KM and US MPH clusters.
Check below to see which matches your vehicle!
E30 VDO US MPH - (missing plastic cover in photo)
E30 Motometer US MPH