so basicly i should change exhaust and done?

hello. I'm try to do this mod and acctualy i have something like this:

https://www.youtube.com/watch?v=qkyHhQIRK7E

lc can generate about 0.4 b but only on hi rev about 7k rpm, and also i don't have flames form exhale, why?
start from lc is more laggy than without it...