I just put on the American Custom pipes today. I put in the short mid rumble baffles. Wow. I was able to turn up the TFI considerably. Went from 3 to 6 on the accelerator setting and also raised the idle mix a little and the main up from 3 to 4.5. The difference is considerable. I feel the biggest difference in third gear roll on power is much better also the 70 -80 in fifth is much stronger. On the down side I went from 41 to 36 mpg but I was really riding it hard for about 60 miles and then I refilled to get that mpg reading. Need to run thru a few tankfulls. Now if it would ever get warm. 45 degrees on the way home 15 mins ago and left the cold riding gear at home.