I did the mod. 170 mains and 20 pilots and at first i add a really bad bog at 6000 rpm . Tryed messing with holes, pluging them with tape but it was worst. So i raised the needles one slot (lowered the clip one slot). Not only it as more power it sounds awesome and the snow dosent get sucked in the air box so much. I Wish i would ave done the mod a long time ago.