Nice mod. I installed a 3.38 LSD unit from Diffsonline into my 330i 5speed about 2 1/2 years ago. By far this was my best modification I have made to the car! I am running stock intake and exhaust so I don't have to worry about added noise from the higher rpms. I am pretty much always at 22mpg with mixed city and highway driving.
A friend runs a 3.64 lsd unit in his '05 ZHP 6spd and it is a rocket. I love this gear with the 6spd.
Traction possible thanks to a Diffsonline 3.38 Limited Slip