Addressing the elephant in the room..

I recall from changing out the brake lines in my M3s to SS lines, that factory brake lines actually were stainless steel lines covered by rubber on the outside.
Not to mention that I haven't really noticed better response from the new SS lines vs. old. Brake fluid made that difference.

What are your opinions on replacing the brake lines on 944s? Do stock lines work just as well if not better than aftermarket SS lines? I would imagine their QC isn't too shabby..

 

Much of the time any "improvement" in braking comes from purely replacing aged-out old hoses; regardless of steel or rubber new ones.

Rubber brake hoses are so thick walled and stiff that they should contain most of any "pressure expansion" that SS hoses are sold as a fix for on their own.

So really, whichever you can get a better deal on for a quality part will be fine. I put SS lines on my car in 2006 because that's all that was available at the time. But on 2 of my Subarus I have put new Centric rubber lines on when doing a brake job. Works great either way.

 

I replaced my front SS lines (due to being 10yrs old) with new ATE rubber hoses. I couldn't tell any difference. Gonna do the rears next.