Well no real world experience yet because I just went through this and nothign has been received yet let alone been installed. Here are my conclusions & rationale in case it is helpful:
Shocks: I went with Bilstien Sports I didn't think I needed anything more. I considered a coil over but the adjustablity would simply confuse me at this point.
Sway bars and mounting upgrades? I went with Suspension Techniques pretty agressive but not too aggresive. I wanted to use softer springs as opposed to the hard springs soft bar approach. I am making my own reenforcement plates a la Turner but will likely regret this. Should have ordered their reenforcement kit with the shocks and springs.
Springs, rates, linier or progressive: H&R Sport - moderate drop, well liked, good first step. I have a 91 318i so model specific option was useful. I went with the 91 model versus the older 318i model which provides some rake (lower front)
Full urethane suspension bushings: I am renewing all bushings with stock from Pelican Parts - cheap. Considered eccentric trailing arm bushings but will go to the bimmerworld rear eccentric mounts later if needed or desired.
Front control arm offset bush? brand and type Previously done Offset from Pelican Parts
Adjustable strut tops; street compliance such as K-Mac stage 1 Renewing stock will adjust if necessary
Rear sub-frame camber caster adjustment modification; Irelend Engineering or other Considering bimmerworld mounts
Other All other rubber shock, and spring perches, Reart subframe bushings are being replaced with new stock. Rear shock mounts with OEM E46 mounts from Pelican Parts.
These decisions were based on a car that is 98% a daily driver. I want the car to be tighter with less roll, but still capable of taking rough(ish) roads. I have a 2004 Cooper S and did not want a car stiffer than it. Once suspension work is done, next on the list is driving school and auto cross. After that adjustabilty will be considered.
I stayed away from urethane because I want to retain a daily driver. Also I wanted a minimal approach that I could learn from and then adjust.