Opening and smoothing the bore plus removing 90% of the throttle shaft and the screw heads/extra threads will net about 5-6% more area for air to flow through the TB. This is a crucial entry point for air flow into the UIM and it will make a noticable improvement in how quick the engine climbs through the mid & upper RPMs. If you don't get a noticable response from this mod, there may be restrictions either upstream in the intake or downstream in the exhaust.
