I am about to place an order of Powerflex bushings for my E32's control arms and thrust rod from bimmerworld.

Now, I am faced with a question that I hope you guys could answer.

Under control arms, two options were given..........1) for steel control arms; or 2) for aluminum control arms.

How would I know which one I have?

My car is a 1991 E32 735i manufactured in 9/1990.

Thanks!

Use steel!
-cheaper
-more rigid
- on steel ones you can change the bush

200 gramms difference does not matter at all, I talked to a now retired design engineer in Munich about this. Reason for the change from steel to alu for the control arm on the 750 was to get possible vibrations in the sus better under control.
Did not help much according to him.
I changed to steel on all my E32 750 and the Alpina B12 5.0 cars also.

Powerflex bushings: reconsider to use Meyle HD bushings, but that is your choice.
See under HD spare parts
http://www.meyle.com/html/index.php?lang=2

Use steel!
-cheaper
-more rigid
- on steel ones you can change the bush

200 gramms difference does not matter at all, I talked to a now retired design engineer in Munich about this. Reason for the change from steel to alu for the control arm on the 750 was to get possible vibrations in the sus better under control.
Did not help much according to him.
I changed to steel on all my E32 750 and the Alpina B12 5.0 cars also.

Powerflex bushings: reconsider to use Meyle HD bushings, but that is your choice.
See under HD spare parts
http://www.meyle.com/html/index.php?lang=2

Actually, I was asking how would I know which control arms I have, steel or aluminum, as the order drop down menu for the bushings asked which ones my car have.

But, somehow, you also answered my question. So, I guess my car does have steel arms, as I had suspected. And the 12-cyl cars have the aluminum.

Thanks for the help! :)