Here is a simple way to put the clutches. If you plan on running a low maintanance setup then run a carbon clutch with a softer spring. If you plan on running the fastest possible setup then run a firmer spring with alum shoes. The carbon clutch will not give you that snap and just wear down faster if you set it up to snap. The alum will bite properly if it's set up to snap. However, you will need to sand off the excess alum like every 20 minutes of running. A simple way to put it is, if you are racing sand it after your heats and then after an extended main. All you are doing is removing the excess material, you aren't trying to actualy sand it down. The carbon will just turn the dust, but the alum will just stay in the clutch and build up untill it causes problems. That snap is caused because the typical nitro engine has more torque as you get closer to the middle of it's power band thus it initialy starts with more torque. It is funny how hotbodies has had a 1/10th scale truggy out on the market for the longest time that has not recieved any attention and now the mini jammin is getting tons of attention.