HPAutosport knows their shit. This is so weird. If you were local I would force you to take my car for a spin. If my car sounded like yours I would never drive it.
There is a right and wrong way to install the bushings fwiw:
There is a flanged face on them.
From the turner install instructions:
C. Each mount needs to be pressed in from the bottom of the sub-frame (the flange on the mount faces
the ground) NOTE: The factory BMW bushings where installed the opposite way (from the top of
the sub-frame).
Bimmerworld: "Both front and rear aluminum subframe mounts install with the flange on the bottom. This may be different
than the stock mount orientation that may have the flange on the top. The “stopper” washer originally used
on the bottom is not re-used."
It is interesting bimmerworld says their bushings are for all E9X where as turner has separate ones for the m3 and non M e9x.