Hi, i've been trying to pinpoint the exhaust diameter just before the catalytic converter. I want to purchase 4-2-1 headers which come with a test pipe to replace my cat. (See: https://www.protuninglab.com/hds-ha94l4-hfc-ha94.html) After this i'm installing Yonaka's cat back system with resonator and a nice quiet muffler. (See: https://www.yonaka.com/ProductDetail...C9497&CartID=2) I am trying to make sure that the outlet of the test pipe matches up with the Yonaka mid-pipe (after the cat). Yonaka states that their kit is an OEM bolt up. Now i'm not sure what the OEM cat outlet diameter is. I couldn't find it online, and i'm hoping for it to match up, god please match up.

 

Most times when an aftermarket manufacturer states that it fits a certain chassis, it is to OEM spec. Any time I have looked at aftermarket exhaust specs they will state right in the specs that it is a different diameter/size then OEM. Make sure to buy the header and exhaust for the same engine and trim and you shouldn't have any issues.