I've seen blips here and there on this in a few other post but I wanted to ask the FI crowd, would it be more of a help or a hinderance on an FI setup to do cattman headers (2.5in) with the 3"cattman cat back or should I just try to find a 3" Y? for the purpose of a 3.5 or a heavy SC setup.

 

For FI, I would go with a 3" Y-pipe and 3" catback if possible. You want the exhaust to flooooow. If not, then the 2.5" headers will still help out a lot over a stock exhaust.

If it's an N/A VQ35, then I would go with headers and 2.5" all the way back.

 

thats sorta what I was thinking, just wanted more opinions. I was also worried that this might look like one of the "dude what kinda Y pipe should I get" threads, LOL just trying to make sure all my info is right while i make out my "to do" list,