13 year model XL883R, intake and exhaust NORMAL mounted in car.
Although it was half-trusted, I felt the difference from the moment I installed it and hung Engine. The engine's beating or firing one explosion strongly, the impression did not change even after running.
The place where 2000 to 3000 rpm was settled was able to respond to Throttle firmly and it became usable, and it became possible to run with one step higher GEAR. If this is so, you can expect a fuel economy up.
It was a new discovery that static electricity had such adverse effects.