Manifold and header comparisons
 

Just bought my first g37 and really excited to start modding... First question is about upgraded manifolds, gonna go all N/A. Any differences between the z-1 manifold and the motordyne m370?

Next is regarding headers; every manufacturer is claiming HP gains but they are all shorty style. The only one I know with true long tube is PPE engineering. Coming from an infiniti I30, this is gonna be fun! Thanks in advance for any input.

have you tried searching?
there a lots of threads on what you are asking.

m370 gains mid range lose top range. Z-1 gains in both mid and top. I think Fast Intentions makes a true long tube header.

Motordyne makes a set of long tube headers that can use their straight pipes, HFC's or resonated test pipes. Kind of a neat setup. They list them for the 370Z but I'm sure they'll fit the G37 as well.