I had the same question...I just installed Bub's with air box elimination kit (K&N pods -- also removed AI). I installed 140 mains but left in the stock pilots because I was having a hard time getting then out. What size are the stock pilots on a 2008 Speedmaster - are they 42 anyway? I set the idle mixture screws to about 3 1/4 turns out. I get a little pop sometimes when reving right after start. Adjusting the idle mixture screw is hard with the D - tool - it's hard to tell when they are screwed all the way in as you don't come to a solid stop.
Performance is good although maybe a little sluggish at low throttle.
