Choice Of Motor For Brushless Jato

Hello, i'am to convert my Jato 3.3 into brushless, and i don't know which motor to take.
I've my ESC and my batteries, it's a Mamba Max controller and MaxAmps 6000HV 14.8 volts, yes, 4 cells!!!

Now i hesitate for the motor choice.

I look for the Feigao 540 8L ( the purple one on the RcMonster store) or a Feigao 380 9L.
I have a lot of 5mm pinion gear, so the 540 with 5mm shaft is a plus for me, but if you think that an other motor will be better for this conversion, tell me please.
I'am not stick on the Feigao motor, but this is the brand that i know better because i have a 540 8XL in my Hot Bodies LSP electric truggy.
I think that Lehner is good motor too but don't know anything about it.

Could you help me please, i want a nitro killer machine.

Thank

David