I have achieved amazing results using the Graves header with the stock canister.  This is a perfect candidate to put the flash for this set up in Low power mode and the normal Graves full system flash in Full power mode.    See you tube video below for a full explanation or scroll down to just see the dyno runs .  All runs are optimized with my flash 

The below dyno run shows the Graves low mount system with Graves velocity stacks vs Graves header with stock canister with Graves velocity stack

The below run shows the graves low mount vs the graves header with stock canister but with the stock velocity stacks