I am old school.

I loved that for a very long time you could go to a GM parts department and buy almost any part for your GM vehicle - be it a year old, or decades old.
Sure you could buy parts via the aftermarket, but 99% of the time, the very best quality parts were sold at the GM dealer - they met or exceeded OE spec, even though Delco may have been on the box, but they stopped manufacturing that part in house years prior...

Those days are a thing of the past.

As an example, I graduated in 1995 and that summer I got my first car - a 1970 Pontiac Firebird;
When I got it my Firebird was twenty-five year old - and from that point, going forward about five years, I often found myself at a dealership getting parts there rather than trying to find them via the aftermarket.

These days, GM seems to have all but abandoned their old model of supporting their vehicles by continuing to offer the best replacement parts on the market.
Case and point:
Struts, clutches, CV shafts for our Cobalts.

Now, I am proposing that a thread be created to collect information of the OE spec parts currently being sold via the aftermarket, but no longer in GM boxes.
I specifically put this thread in the "08-10 SS Turbocharged" sub forum, because those are the cars I am interested in, and if we were to try to cover all three version in one discussion, the thread would probably become a jumbled mess.

I recently popped the transmission off the sedan, and saw that the OE clutch was a 'Sachs' part, and I have understood that the OE struts for these cars were also 'Sachs' brand parts.

I offer the following picture as proof that the OE clutch was a Sachs part:


I recently was looking for the OE struts and I came across this:

LH: GM #19181251 = Sachs #315128
RH: GM #19181631 = Sachs #315127

I realize site activity isn't what it was when I joined, but I hope that others see this and are able to contribute.

 

I am replying with new found information.

I ordered a set of front struts off Rockauto;
One was cited as Sachs, but in a "private label package";
The part was supposed to be 315-217 (RH);
When I received it, it was in a TRW box with part number JGM4437SL.

Curiously when I tried doing a search for that part, it suggested this was a LH part;
It is quite probable that this 'private label package' was the RH part in a LH box, because I did visually confirm that it IS the RH part - but according to my search the TRW boxed parts should be:
JGM4437SL = LH
JGM4437SR = RH

Anyway, here are two more part numbers for the OE struts, not in a Delco box (I'll remind you now that GM actually discontinued them).

 

I am putting this here, because I just came across it.

Incase anyone has found updated or otherwise part numbers, please correct me.

LINK (taken from post #11)

I also found this:

LINK

That first quote was taken from an older thread, and GM has had a terrible habit of randomly changing part numbers, so I would have to guess that what we see above are the original part numbers for the OEM struts issued in 2008;
(GM)19181044 -> (GM)19181251 = Sachs #315128
(GM)19181043 -> (GM)19181631 = Sachs #315127

The shocks are a bit of a confusing matter all together;
At a glance (see image above), it looks like the Sachs number is also the GM number - but I believe that Sachs just printed the GM number on the label for parts that were (possibly) sold to GM/Delco - it appears as though Sachs uses a six digit part number, while GM has been using a longer part number for some time.
I looked further into the shocks, and it appears as through GM may have superseded the 2005-2007 FE5 shock with the 2008-2010 FE5 shock;
Crate Engine depot lists the (original part number) as being for 2005+ (LINK), and Rock Auto similarly also shows the Sachs FE3/FE5 as the same part - so it is possible that GM also ended up superseding the FE3 shock with the FE5 shock.
It also looks like the the GM to Sachs numbering may be:
(GM)25793745 = Sachs #030871