Poly bushings are falling out of favor because of their limited lives with an abrupt failure mode, additional noise transmission and harshening the ride without adding much if any improvement on anything but track cars.
Not being a 3 person--I can usually recognize one though--do the Regular 3s use the same bushing size as the M3 in the same E series?
The trick on the big cars is that E34 E32 and E31 share front bushing sizes. So you go with the E31 aluminum lower arm that has a spherical bearing rather than a bushing (Fits E32 and E31) and an E34 M5 top rubber bushing (Fits E34 E32 E31) and you are beyond anything you could do with Poly for turn in but still have quiet and smooth.
So maybe going to M3 bushings would feel better?