Ive had a couple of people tell me that the factory ones are better than the aftermarket nolathane ones. 2 reasons - The strngth of the polyurethane plastic is higher than rubber, but when it fails it fails catastrophically. When rubber fails, it starts to tear, which is usually not catastrophic.
The other reason is that the rubber one is softer, meaning if you thrash it too hard, it will bounce and hit the bumb stop and transmit the thump to the cabin and you will hear it, and probably ease off. In polyurethane, it probably wont h it the bump stops until after failure...
I have just recently swapped from a 3:08 open (7.5" crown) to a 3.7 (8"inch crown) and went with rubber. its a good move. No failures (yet) and its not crashing and banging when i give it the berries on the skid pan.
