I talked w/ Jeff a few weeks ago and he said that they were developing two pipes then, but would be desciding on ,"maybe just one for production". Give them a call to find out which one works best for what you want. I know that you only wanted info on 01, but I have to throw in that, until this year 02', I have used Bill's Pipes for the past 8 yrs on all of my Honda 125's, w/o any problem w/ them and they helped out a bit everywhere in the pwr-band. I currently a run an FMF Fatty/shorty, and it is wicked. Good luck-