I highly recommend the FVD Brombacher 'sound version' muffler.
I installed mine in 2010 and have worked with a few others on choosing this muffler (10/10ths, Por356,,,).
After 8 years I still love the sound and it still looks like new. I added Top Speed cat bypass pipes, which turns up the volume to the perfect level, reasonable at idle and around town, and pure Porsche flat 6 sound under acceleration.
Reports are accurate, absolutely no drone, likely due to same outer case design as OEM muffler.
Rhonda may give a forum discount if you contact her before ordering. Mine was approx. $1100 back in 2010. .
(Installed with rear bumper in place)
