Well based upon my research it seems that transmission and engine mounts will have the biggest impact on NVH and subframe bushings not so much.
But I'm hoping to get first hand input from someone who got these solid bushings.
I want to improve rear end stability and grip for the most.
Another reason is that the M3 subframe bushings have induced or amplified some weird resonance noise. This does not happen on alot of cars but it did on mine. So getting solid mounts may get totally rid of this, or make it worse than hell
Performance Seats, Exhaust, Splitters, Pedals, Steering Wheel / RB Turbos / M3 CF Roof / Brembo GT BBK 355/345 / Rollcage / Forge FMIC / Quaife LSD / Íhlins Road & Track / M3 Suspension Parts / Powerflex Bushings / Vorshlag Camberplates / Megan Racing Toe Links / LeatherZ Gauges / Extended M3 DCT Paddles / ER Sports OC / AR OC / Aux Radiator / AR DPs / Alpina TCU / COBB Pro-Tune