Keep in mind those 40 series tires are gonna put alot more load on your drivetrain, ESC and lipo's, especially on 6S. You may experience more differential failures from that extra weight and you wanna drop down your pinion tooth count or the extra load could fry your ESC/Lipo's.

I recommend getting the bulletproof diff upgrades and the castlink so you can modify the ESC to your liking and get used to the speed and power of the Flux.

The 2200kv motor with the Flux is pretty hard to beat without spending alot more money, its a high end brushless motor for its price range so I'd drive the truck with that first before you get any crazy ideas of a high end sensored Novak or Tekin BL motor