In Reply to: Damage to Undercarriage from Speed Bump? posted by Rick/Los Altos on November 12, 2000 at 19:09:17:
"...I notice that there is kind of protective skeleton of black metal tubing under the front of the car protecting the drip pan and the transmission."
That is called the BMW X-brace. It was designed and bolted to the bottonm of the frame to provide additional chassis stiffness. All e36 convertibles and roadsters have them.
Not only does it make the car stiffer, it is responsible for the phenomenal turn in of the car but it also provides some protection to undercarriage dings.
Provided the ding was hard enough - "when in doubt, have it checked out"