There is not a lot of room in there !
Traxxas ones are over priced in my opinion .
Hobbywing make a 16BL30 which I have seen on Youtube in the Traxxas 1/16 .
30 amps seems a bit low but they seem to work in the videos .
A Hobbywing 10BL60 would be more to my liking but probably would not fit as good .
I have seen the ESC mounted on its side , as well as people cutting the chassis to fit an ESC in the battery compatment .
Which ever you get , you will probably have to solder on a battery plug and possibly bullet connectors for the motor .