On my old 135i, I did the M3 front parts and the rear M3 subframe bushings (all done myself) and the rear was more noticeable than the front. It is the same rear carrier in the E82 to the E9X, so it's the same job to replace the rear bushings. Not for the faint of heart, and suggest sourcing the proper bushing press, if you are doing it yourself. I made mine, and it was harrowing.
You didn't mention if you track your car, but you did mention that the roads are bad where you are. These modifications you are contemplating will stiffen the ride. So unless you are tracking the car, stick to OEM - or the M3 parts.