I saw this from a vette guy who had a similar problem. A lot cheaper solution if you think it would work.
"Here's my solution: 2'X2'X1" rubber tiles. I've got a 1 1/2" drop off the end of my driveway into the road. My air dam would drop hard into the driveway and scrape for the last 6 inches or so till it cleared. Also my front splitter would scrape if not at an extreme angle. Now no scraping at all. They are called 1" eco-tiles and are made from car tires. here's the link: http://www.rubbercal.com/Eco_Sport_1_Inch.html"
There are also some cheaper options more like the others here:
http://www.discountramps.com/curb-ramp/c/4240/
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