I just put some in my buddies 06 Gen I with Airbox mod and Brocks GenIII exhaust and did this past weekend. Anyhow, the bike baselines at SAE 156hp on a Dynojet 250I. I use ECU editor and the tune is around 13.2 to 1. With the MR12 fuel I richened it up and got the AFR to 12.90 to 1. We gained 5hp from the fuel. We could have leaned it out and gained more HP on the dyno but I leave it there as on the road the AFR will lean out some.
In the past I have used MR11 on a 2007 GSXR1K that baselined at 157hp with a slipon and no tune with a AFR of 13.6, it gained 6hp and leaned it out even more. This bike liked it lean as it picked up .2 and nearly 3mph in the traps. I have also used MR9, U4 and U4.2. They all gave about 4hp without a tune. Only ever got an additional 1.5hp on the dyno if it needed to be leaned out.
All these fuels work but I have never gained as much as everyone else in the US. Now you can't just say you will gain XX amount of HP but you should look at the percentage gain dependant on how much HP you have to begin with.
Note: We used all 5 gallons of fuel after making 35 runs.
And yes, if you leave the fuel in the tank for too long such as over a week, it will gum up the injectors, fuel pump and even the valves. Fill up the tank completely and run the engine on regular pump for at least a few miles at the mininum. Other than that, these fuels stink bad!
For the price of admission, a little expensive for my taste.