We have enough 3 series bimmers over here, no thanks
Seriously: You have to calculate the shipping, import tax (if you stay longer than one year with your car into the referring country) and the following modifications:
Rear lights from red to red w/yellow turn glasses
Headlights for Europe with e* marking
Code in rear fog lite, this goes almost together with a headlight switch change if you haven't this already installed
Relabeling the speeding scale (no matter with mp/h and km/h as long as the metric scale is listed)
In Germany you have to present your car after all to the TÜV organisation for a §21 inspection. This is necessary to get the correct papers for the insurance and number plates.
Front bumper numberplate holder, rear numberplate holder for european numberplate sizes.
€dit: Forgot to mention the deletion of the side reflectors from the front fenders
Additionally: Reload NAVI database to EUROPE NEXT or whatsover your current version may be, Recoding TMC to ECE if you haven't RTTi, the radio tune frequency steps have to recode also to receive the FM transmissions here, SOS Emergency won't work any longer caused by different signals into the SIM-card carrier, a box change isn't recommended from my side.
So far for the first steps.