Thanks for the reply it's running standard suspension and not to sure what wheels they are
From hour pic looks like your are running the original 16inch Zstar alloys.
Those could do with 25mm on the rear.
Probably 10 on the front.
This clip shows how to measure
View: https://youtu.be/3LeFZsyGRrs
ALWAYS get hunbcentric ones. I believe the hubcentric are at least 10mm upwards as the lip on the standard hub is 10mm so it must be at least the same or more to clear it (hub centric ones have their own lip just like the standard hub, don’t go for flat universal ones.
Smallest I’ve used is 12mm
Plenty on eBay (search e36)
top tip - remember they will come with longer wheel bolts - don’t confuse the bolts - as k me how I know (put a longer bolt on and didn’t have the spacer fitted