The factory underbody panels work well for the most part, but over time they can become weak and break loose. When this happened to me, I had no choice but to replace the panel. As you can see, it is totally useless and was dragging on the ground.
Rather than risk it again, I upgraded to the aluminum underpanel carried by our sponsor. The kit replaces the three panels and consolidates them into one large panel. It also includes a steel guard, but I did not us it during final assembly because it made installation harder (nearly impossible to align without two people, and I only had a short time to install it), I didn't like the way it looked, and most of all I was afraid it would scrape a lot. It is supposed to improve aerodynamics though.
<span style='color:gray'><span style='font-family:Courier'>1995 e36 3 Series RIP
1999 e46 3 Series BURN IN HELL
2000 MR-S Roadster= Current</span></span>