I have a 2003 325i and am wondering if anyone knows how hard it is to upgrade stabilizer bars. I'd like to increase the diameter. The rear looks very easy but am wondering how easy the front is. Any advice? Thanks.

The front is easier than the rear. The rear is easier if you have access to a lift... gives you more room to maneuver the old bar out.

I agree with ZHP. The front is easy to get out, the rear requires a little wiggling to get it to clear the exhaust.

Be warned that the rear anti-sway bar mounts are notoriously weak in the E36 and E46 and can break off with a stiffer bar an no added reinforcement. I had the Turner reinforcement kit welded on before I put the rear bar on.