Rear Track/Trailing Arm Part Number
 

So the arms I ordered from Vertex Auto came today. The part number on the box (986 331 043 07) matches the OEM number, but the part number on the arm (986 331 143 06) doesn't. Also, it doesn't say TRW anywhere, and I can't find the part number on the arm on the Internet either.

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So I checked the arms currently on my car (2001), and the part number is 986 331 143 04. It seems like these arms are the newer version, but I wonder why it's different from the Porsche part number?

Are they originals or knock-offs?

The ones on the car right now? I don't know, should be original because I've had the car since 80k miles until now, 140k, and I doubt the guy replaced it right before he sold it at 80k. The ones I got from Vertex are supposed to be TRW!!

Interesting issue.
Pelican confirm the correct #. You might call them and ask.In my experience they will research an issue like this and get back to you:
Project 59: Front/Rear suspension Overhaul - Page 1
You may also find this Parts diagram(see #8)from ******************************************** useful:
Rear Axle Wheel Carrier Control Arm Wheel Hub

I just emailed them. Let's see what they say. I was hoping that somebody with a TRW or Porsche arm could show me what part # is on their arm.

I was able to check part # on the drivers side arm without removing anything. If anyone needs something to do and can check out the part # on their car for me, I'd greatly appreciate it.

I have a couple of '98 OEM arms on the shelf.
Number cast into the part is 986 331 143 04. Not sure which side this is for (only checked one).
In the area where yours is ground down next to the p/n there is a triangle shaped logo.

Thanks. That's the same number on the arms currently on my car, which I believe to be OEM. I think left and right are identical, so only one part/number. I'm curious why that area is ground down on mine. Does yours say Porsche or TRW anywhere at all?

I did not see a Porsche logo, only the triangle shaped one. I got some front TRW's recently, and I noticed they had a similar spot ground off also.

Some more info in this thread
http://986forum.com/forums/performance-technical-chat/53590-rear-suspension-noise-over-tar-strips.html

So I replaced both arms over the weekend. What a big difference. No more loud clunking noise, and the rear doesn't bounce that much over uneven surface anymore. I should've replace these a long time ago. As for the part number, the old ones on my car had part #986 331 143 04, with the triangle logo just like spendy said. My new arms from Vertex, supposedly TRW (they never got back to me after I emailed them asking about the different part numbers), don't have the triangle logo, and have part #986 331 143 06. I compared the new and old arms, and there's a difference in the beam profile, or curve. But still, the new arms fit exactly in place without any problem.