Exhaust Drone after lower torque mount bushes

Hi All,

After installing powerflex purple lower torque mount bushes I seem to have what sounds like exhaust drone around the 3000 rpm range. I know and expected some NVH and feel the vibrations at idle or creeping and I am okay with that. It's just the noise at around 3,000 RPM gets quite deafening.

Has anyone else had that after the purple powerflexes? I'm wondering if I and have put it in too tight