There is a small increase in performance with the bigger diameter crank. The lifespan, i cant comment on because i've only had a few runs with the SCT, but it seems to be holding up really well so far. To extract maximum life from ceramic bearings, run good quality fuel like Runnertime, and after each days racing, take the engine apart, make sure there is no fuel left in there, clean with alcohol, and oil liberally while re-assembling. A good quality after run oil like Mugen or Powersave is better than Automatic transmission fluid. This is a good way to prevent rust, and the corrosive nature of nitro doing it's work on your bearings and internals between race days.