My first converison losi 8

Well I recently pick up a used Losi 8ight rtr on retech for hella cheap.This will be my first ever brushless conversion and a rcm mount .It was supposes to be my race project but school started no time to go to the track.Running a neu 1512 1.5df on 4s spc 8000 in series.Mounted on a matrix carbon fiber chassis(couldn't afford the shock towers)

Its also my first time ordering from RCM the first thing that I notice was that shipping was super quick.Bushless motor mount,some caps,and a 16 tooth mod1 pinion.I order on Sunday and receive it on Wednesday.
Here is a teaser pic


So what do you guys suggest for the spur how many tooth?
I'll get more pic tomorrow.