anybody ever buy and install an aftermarket header on their xj thinking of getting one to go with the intake swap im doing. any noticable improvements after install?

 

If you are getting one just get an apn they are pretty cheap, your not looking at any big improvements

 

A lot of guys on here run the apn header without any issues. I installed a Borla header on my 99 after the factory manifold cracked. You wont see all that much improvement from just a header, but like most you won't just stop at a header. Sooner or later you will want to replace the entire exhaust.