Do you need a PCIII with a slip on?

A friend of mine is wanting a TBR or Yosh slip on for his 05 F4i and is not sure if he will need a Power Comander or not. He has talked to a few dealers around here and has gotten mixed opinions. Some say it is a must because it will not run right and others have said it only makes it run better. I was always under the impression that it was not needed but could get you a few more HP by using it.

Thanks for any input,

I asked the same question for reference about a month ago. I most likely had my answer from my local parts dealer (indysuperbikes.com). A power commander with a slip on is most likely not necessary. It is for fine tuning and to adjust how much power you want. I installed an M4 slip-on on my 02 F4i about a month ago and have never had any issues.

I've had my Yosh slip on for like 4 years with out any problems.

I have an '04 with a TBR slipon and I also have the PCIII. Before I installed the PCIII the bike did run stronger than stock but when I installed the PCIII my mileage increased substantially. My personal reccomendation is to get a PCIII for sure.