The peak number was a loss of 2 HP at 8000rpm compared to stock with aftermarket exhaust. I don't remember what the torque comparison at 8000 was. I will look it up if your interested.
Bmw published figures are at the crank. On top of that every dyno reads different so that is why accurate comparisons are usually done on the same dyne. My peak HP figure was 98 Hp compared to 100 from a identical ST1200 to mine stock with a exhaust system. I was extremely happy with the results achieved with the PC3 because of the hugh gains in the midrange and a loss of only 2HP at 8000 rpm where I rarely if ever see. I knew going in that there was going to be a loss at peak rpm but thought it would be more based on what others using the sprockets have said, however, after seeing the AF ratios with the FRK module we thought the HP and Torque lost could be gained back. We not only gained some back but increase more in the low end and midrange with just a slight loss at 8000rpm where you rarely see anyway.
The HP and torque my bike has is enough for my riding style. But I think the engine is not smooth unless the ambient temp is around 40-45 deg F. So, I'm considering the booster plug.
But, I want to know if the richer mixture can damage the engine because it's too rich. I doubt it because from the factory it's mapped very lean and the increase in fuel brings it to what it should be.
If you are looking for a smoother ride when tooling down the freeway (or other roads) at a steady state the Booster Plug or the Accelerator are not the device you want.
It's already smooth at constant throttle. I want the engine to run better at varying throttle like when you start off from a stop.
I run an IICE Air, which is similar to a BP. It smooths things out a bit at part-throttle, but really makes the bike punchier when you're beating on it. I like it, and for $75 it was a bargain.
I have found a much steadier idle and a much smoother & more consistent low end rolling on the throttle. It was an epiphany for me.....
Installed booster plug on G650GS Sertao last month. GREAT help on starts and manuvering at low rpm. There's a photo of the install in my albums.
If so - I might actually consider trying one. My bike was running particularly sweet this AM with the temps in the 40's.. so running a tad richer may be what it really likes. Of course my suspension also felt better this AM, so I'm guessing I have to up my damping adjustments a click or two when it's hotter out. Or it might all be imaginary and I was just really happy to be out riding in December..