Which leads us to wonder if the Throttle Body is the 'bottle neck' in the system. In other words, would that last 20% opening net any increase in power? I've swapped to larger throttle bodies on other turbo motors (Mopar2.2 stuff mostly) and had no gain in performance on a reasonably stock motor. Yet with the same platform engine on another application that was built up with big valve head,ported/polished manifolds, aftermarket pistons/rods etc, I gained almost 20WHP going from a 52mm TB to a 58mm TB. In that application, the TB was clearly the cork.