Sirio .18 tuned Pipe sucks
Yeah i would focus on tuning. i know when i switched pipes it was a bear to get the carb in tune. Eventually after i had run it a while with it one there i finally hit the right spot. wasn almost like when u break it in, took awhile for system to mesh together to run at peak. Just stick with tuning, i must oh went back to factory specks and started over a dozen times.
also, i dont know anything bout sirio pipe, but if it is a regulated pipe (like the cvec) u have to set the low speed first then the high speed, opposite of norm.