[Brucelee]

As I understand it, you don't buy a "rebuilt" engine from Porsche, you buy a remanufactured engine. This means that the core of the engine is new, the peripherals like the FI, exhaust are refurbed.

Now, if you are buying from someone else, I have no idea what you are getting and you likely don't either. As I understand it, Porsche makes it very hard to rebuild an engine, in that they don't regularly sell OEM internals to the rebuilders.

Hence, I think if you are buying from a rebuilder, he has to source the parts from the aftermarket.

I believe the above is correct.