Having recently removed the engine and gearbox of my 997 to replace all of the coolant pipes / hoses, sensors, starter motor, alternator, etc, etc, about half of those parts were OE Match from Design911.
The guys on the other end of the phone are helpful, friendly and knowledgeable. The delivery is quick and well packaged.
The fit of the OE Match parts is good.
Bad points?
Sometimes your local OPC can be cheaper, equivalent in price, or not much more expensive for OEM parts.
I had one coolant pipe that turned up damaged, so check your parts before you fit them and throw away the packaging.
All in all, I wouldn’t have any hesitation in buying from Design911 in the future.