Hey Haman,
Finally a 370Z owner from Qatar on this Forum. Welcome Bro.
As far as headers goes... Fast Intentions offers the only Long tube headers for the 370Z...
My personal route for my 2013 Z would be F.I Cat Back Exhaust with 18' Resonator and F.I Long tube header coupled with Stillen Gen3 Air intake. UpRev programming to put all these mods into the right direction
F.I 370Z Parts