I just got this manual 6-speed G37 and i was trying to get it to stage 1. Does anyone know the requirements? what do I need to get in terms of upgrades before I get a tune. Also anyone know any reliable tunes?

 

Welcome to G forums!
First and foremost, please use the search function - there is a ton of great info on these pages already and all of your questions have likely been answered.
Verts share most of the components with coupes so whatever this "stage 1" might be (there answer will likely be different, depending on who you ask), you will most likely find the details on the coupe pages.
Vert section is mostly dedicated to vert specifics like rear suspension, roof mechanism, etc.

From tuning perspective, ECUTek has been very popular and that's what I used with my car. While OTS tunes can work ok, it's always recommended to get the car dyno-tuned based on your modifications, power goals, and issue tolerances.