Hey, I just installed a HMF slip-on aswell. I couldn't pass on the price. Sounds awesome at idle and when blipping the gas but it is rather loud, does run rather well for not jetting. Does feel like I lost alittle top end or maybe it's just because I have that fart can on a civic thing going. Lots of noise but no go
Did your quiet core insert help a lot? I'll probably just order the quiet core and make a screen to take the space of the spark arrestor. The spark arrestor is expensive by itself, plus I'm not worried about catching the streets on fire
