Choose my BL Motor!

[Skelbow]

My cousin has a full FLM Rustler running on normal sized maxx tires (velocity 6s + Maxx Mashers)

Now he used to run a Novak 5800SS system on it, with 7 cells, and to be honest it actually ran really well, great torque and good top speed!

Now the question is, he has transferred the Novak 5800SS system to his wheelie king, and is wanting something more for the rustler.

He will run 7 cells normally, and 9 for fun... so I am looking for a motor that would work well for his situation, pretty much like the 5800SS, but with the ability for 9 cells...

what do you guys suggest, would a 5700 work? (trucks probably like 6.5 lbs) or would he be better for like a Feigao 9S or something?