Drag blocks...

Drag blocks are great for anyone who want to make nice pretty sparks without messing up the frame. These block are not cheap, anywhere from 30$ to 90$. You can also make your own by fabricating a bracket with and thick piece of metal on the bottom. Simply bolt it up and bam, you're set. These work well for truck that don't quite lay frame but still want to make a dent in the road.
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You can get these at Air Slam