Yes, the diffuser is what I was referring to. As I said earlier, instead of drilling the holes out I basically cut the center of the bottom out. On my 330 when I cut the bottom out I didn't see any gains until I chunked that screen and it was a new saw. Both of you, thanks for confirming my findings.
Yeah I hear you on cutting the bottom out as I will sometimes "V" both ends of the diffuser on the little Wild Thing type saws. That seems to work well also.