Took the time to try a few different flywheels in our 370Z over the last few weeks, The South Bend is definitely the quietest available.
The 18lb unit is VERY loud under 2500 RPM under load and rattles like a worn out diesel at idle.
The South Bend is completely quiet at idle and rattles some under 2500 RPM under load with a rigid disk, It is quieter with a sprung hub clutch and not bad at all compared to the 18lb units which are unbearable to me.
I did this so you guys can make an informed decision on flywheels
Sorry I can't figure out how to get the videos to show up in the post.
18LB AC* (Yes I said 17lb in the video)
Zspeed Performance Nissan 370Z Flywheel Rattle 18lb - YouTube
South Bend DXD Flywheel Below available from us. This was taken with our ZSpeed Rigid hub TZR clutch kit which is a bit louder than the sprung hub clutches.
ZSpeed Performance South Bend DXD Flywheel in Nissan 370Z - YouTube