This afternoon I made up an air dam for the Metro.
Here is what I started with. Its actually closer to 9" of clearance, but with holding the tape measure and the camera you can't tell.
I used lawn edging from the local big box store. I think this whole coil was $5.
I also picked up a bunch of L-brackets at the store. These were about $.70 cents each.
Using existing holes in the bumper (and drilling one here or there), I put some bolts through it to hold it in place.
Here is the finished product.
Still plenty of ground clearance, even for winter I think.
I have only driven the car once since the mod. Its not a familiar route, but it seems to coast a tiny bit better. I maintained speed down a hill where I normally loose speed slowly.