About to get a used set of these for my 04. A guy with g35 is selling them to me used for real cheap.

Any issues with CEL with these?? Do I need non-foulers?
ALso what performce gains are to be expected from these??

This will be my first mod!

Thanks guys.

 

not sure on ur 04 but on my 06 i def needed it...

 

Some answers can be found here.

https://my350z.com/forum/2003-2009-nissan-350z/197329-the-top-100-common-questions.html

For performance gains, you won't get any hard numbers out of anyone but test pipes are definitely a worthwhile mod. You might try searching for dynos.