Are all ECUs the same for 325I cars?

#1

Are the 87 cars different? Or all the ecus interchangable for all the 325I cars?

#2

Interchangeable, but different. The #525 ecu has a 200kph governor that works out to about 112 actual speed or less on race tires.

I’ve heard/read that the 153 is actually a motronic 1.1 but can’t verify that.

#3

[quote=“turbo329is” post=71323]Interchangeable, but different. The #525 ecu has a 200kph governor that works out to about 112 actual speed or less on race tires.

I’ve heard/read that the 153 is actually a motronic 1.1 but can’t verify that.[/quote]
A 153 is Motronic 1.1. The differences between 1.1 and 1.3 are better idle control and support for the stomp test. Any other differences are so slight as to be negligible.