Want to upgrade my exhaust from stock. Want a little better sound and some more power. What should I be thinking about the fmf or the yoga? Pros and cons?
The FMF has two muffler options, PC4 and Q4, and two header options, Megabomb and Powerbomb. Both mufflers have USFS spart arrestors. The Q4 also meets the USFS sound limit. The PC4 produces more power at the expensive of more sound output. The Megabomb header performs a bit better than the Powerbomb. However, you can not reinstall the stock heat shield on the Megabomb and you can install it on the Powerbomb.
The Yosh RS-4 comes in only one configuration (muffler and header). Performs as well as the FMF PC4 with the Megabomb header and produces similar sound output. You can reinstall the stock heat shield on the Yosh header.
In both cases, to maximize the performance increase of either the FMF or Yosh systems you should increase air box and air filter performance as well as improve fuel delivery with the EJK controller. You can replace the air filter with the K&N air filter and remove the snorkel. Some also use our air box kit.
Air Filter
https://www.crfsonly.com/catalog/produc ... ts_id/6440
Air Box Mod Kit:
https://www.crfsonly.com/catalog/produc ... ts_id/6620
EJK:
https://www.crfsonly.com/catalog/produc ... ts_id/6461
We also offer performance packages for each of these exhaust system that includes the EJK:
https://www.crfsonly.com/catalog/advanc ... ce+package
Ken