Because Ielasi has direct access to the production he can use his own CNC programs to make a lot of his own specs by machine. Having 3 Ielasi tuned with all exact the same specs and no sight of hand tuning I am pretty sure it is just machine work. I can imagine that teamdrivers do get some extra handwork on the engines.

Other engine modifiers have to deal with an off shelf engine and have to grind all the specs into the engine.