MOKI 1.8 header exact fit I used a MAC PRODUCTS and the stock noise level is way below any sport glow engines .
I have done a lot of DB tsting - and on this one -I did not bother -it is quiet. mellow no nasty piercing sound.
the little can that comes with it has a fine baffle - I redrilled mine to make all baffle holes max size - very littl differnce in noise and not much sound difference either .