Hi,
that engine mount is really bad. Also remind that there are rubber parts on each side of the mount that also seems to be gone. So that can have caused the noise whren driving around corners.
I would first replace the engine mount with 987 parts an check if the noise is gone.
Transmission mounts:
Porsche Boxster Transmission Mount Replacement - 986 / 987 (1997-08) - Pelican Parts Technical Article
Regards from germany
Markus