Interesting discussion, and here is a video I posted a while ago, yes, you can dyno a Spyder.
Can-Am Spyder - Three Wheel Motorcycle - Bing video -
https://www.bing.com/videos/search?...E8A6CA422DE3A2C85783E8A6CA422DE3A2C&FORM=VIRE
As for the ECU reflash, I have a 2015 RT Limited, with a one-piece exhaust and the muffler is a fiberglass wrapped can, on the free-flowing side. I can't give you horsepower numbers, or drag strip times, but will say that seat of the pants, my RT seems to have better throttle response, and it is smoother running over the whole rpm range. With my wife on the back, it easily spins the rear tire thru 1st gear, I was taking off from a driveway, and I had no need to do any more. The same thing when passing a car on the road from 65 mph - instead of having to down shift three times like I normally do (and I will say that I have hit the rev limiter (8300 rpm) a couple of times while passing) I only had to downshift twice to get the needed acceleration. Just about the time I felt it was time to shift out of 4th I glanced at the tach & it was at 8500 rpm and so smooth I didn't want to believe it. I can't say any more except my RT is smoother now whatever rpm I'm at, has better throttle response, and my gas mileage is about the same as it was before, as long as I behave myself. I have no regrets, and the folks at Wick-It Performance (in La.) were absolutely great to work with. I'm not a street racer or anything like that, but when I ask, I expect performance back. The only wrecks I've had have been on the racetrack; and I think I understand performance. I've owned a Kawasaki H2 that was warmed over, a Kawasaki Z1, a 170 mph Ducati, and the first Yamaha V-Max in Jacksonville Florida in 1984. I've only been riding for 58 years, so I guess I am really too old to be doing this, I'll be 79 on July 4th.
That ECU flash gives you so much more than just speed, it makes riding two up more enjoyable, and I think my RT is a much nicer all round street bike.
David VonStein
Middleburg, Florida