I would ask what type of riding..track ,trail,....racing......???
In Iowa they haven't been enforcing spark arrestors or db levels (yet.). etc 95-99..dbs..
Do you ride at the local OHV places?... Keep this in mind when buying maybe... To save a headache of having to buy something else. To be legal and quiet while out riding
If you ride other surrounding states .. MN WI... they do enforce these rules and laws...
I have a FMF Q on our bike..It has a spark arrestor .It quiets the bark without any noticeable performance losses.. And it makes it legal to ride anywhere.