I also live in and commute in the Boston area. I used the FCP Euro Lemforder/Sachs ZHP suspension refresh kit a few years back with great results. At the time I also did the M3 RTABs with limiters, added front strut reinforcement plates, added an M3 strut tower brace, and replaced my steering coupler. This past summer I upgraded my sway bars to the ECS tuning 27/21 sway bar kit with poly bushings. In my opinion the car now has the perfect balance between performance handling and driving comfort. I actually drove it to work this morning for the first time in 2 weeks and though not as capable in the snow, it is still a much more fun car to drive than my newly acquired 2013 X1 35i M-sport. The only thing I would love to try on it someday would be a set of KONI FSD shocks and struts. I had these on my prior 2003 330i sport and I loved the way they felt.
Steve,
2004 330i zhp
2009 X3
2013 X1 35i M-Sport