From elbo :Somehow Dale has built it with a more powerful motor that still retains some sensitivity(hope that makes sense)...Ive used other rotarys that have a powerful motor for the purpose of lining but in all honesty they have been ballistic mad machines that require very very careful attention if you want to avoid blowouts!...This new ID hits just perfect on hard or soft areas and lines as true as a train on a track! ..Its also runs smooth and quiet and i cant say ive felt any vibration

Exactly,mate !