That's a good question and I can honestly tell you that in my case I don't know since I did not do a Dyno run before hand - didn't know the shop was there back then. What I have learned about Dynotesting is that all dynos are not equal. If I were to take the bike into a different shop it is likely I will end up with different horsepower numbers. But they are pretty good at tuning a bike by making multiple runs on the same dyno with different fuel mapping and configurations. But I suspect the guy running the dyno has a lot to do with it too since as he explained to me there is the 'dyno world' and then there is the 'real world'. To be frank this is what steered me away from the autotune feature on the PC 5 - that and hanging more hardware on the bike that has the opportunity to be broken later. Looking back on the changes I can say the best bang for the buck as measured by the butt dyno was the gearing change. After that most of the changes were aimed at two things - simplification, weight, and power. I did try a DRD slip-on at one point but I just thought the thing was too loud for what I wanted and then decided to try the old DR650 solution of a GSXR can and midpipe. What I can share with you is another WRR owner's dyno results who start out with the basic airbox mod and butt dyno FMF settings (22.1 HP). He then added an FMF powerbomb, Q4 and with FMF adjustments and got to 24.5 HP After that he removed the airbox door and got it up to 26.8 HP with some additional tweaking. These runs were all done on the same dyno at the close to the same temperature - the first run was done on a different day than the last 7 runs. http://www.wrrdualsport.com/tech-guide/dynotesting/71-dyno2 Can't really compare these numbers to mine since the dyno equipment is different but it gives you a general idea of what gains can be made.