^^what he said, also truggies are lighter in general than MT's and have a higher power to weight ratio, they like to chew plastic ones up sometimes, steel is stronger , and more durable, but on MT's like the revo, the slipper system owns, plastic is fine, metal works to, but plastic is a secondary failsafe, above and beyond the slipper, its the last line of defence, usually nowa days trucks come with both a slipper and plastic spur, a great combo, some dont like my zircon, no slipper, metal spur, can be interesting, l would leave my plastic one on my revo, because the slipper will save it, but l would not run a plastic one on my truggy !