If you use the plastic part that goes over the motor from the gearbox and bolts to the chassis then you are defeating one of the main points of the conversion, and also it will not fit
The turnbuckle can me parallel to the lipos if you are happy to remove a little bit of material from the gearbox halves, the choice is yours.
Btw the speartooth costs more
and our undertray is part of the design of the conversion lol