The only time ceramic bearings will actually help you gain any time off your laptimes, is when you have perfected everything else and have the driving, motor, tires and chassis setup to consistently win races, if you have all that and are looking for that extra tenth that might give you a better qualifying spot or something like that at a big race. I dont see anyone gaining more than a tenth of a second from just ceramic bearings, or any kind of bearings, that sounds like an exaggeration to me. If your friends gained .2-.3 tenths when switching to ceramic bearings, id be willing to bet the time gained was from something else, like track getting faster or they changed to a better driving line around the track, or even got better at driving, something like that would make more sense to why their lap times went down.