First I will answer your questions, but I would like to warn you ahead of time that I do not recommend using the type of brushless motor included with KIT-165 on a go kart, I will explain more about this after I answer your questions.
I do not recommend using the type of brushless motor included with KIT-165 on a go kart because they are electronically very fragile and best suited for vehicles which can be pushed or pedaled to walking speed before applying the throttle and giving the motor power. If the type of brushless motor included with KIT-165 is started with the vehicle at a standstill, it has a high chance of burning itself out, literally in a cloud of smoke. They work great and are reliable for scooters and bikes that are pushed or pedaled to walking speed before applying power to the motor though.
What I recommend is using a brushed motor for the go kart. Brushed motors can handle a lot of abuse and can be started from a standstill on flat ground or even going uphill. We sell motor kits equivalent in power to KIT-165 on the same kits page that the KIT-165 is sold on, they are items # KIT-105 and KIT-106. KIT-106 is a 100% complete kit that includes everything from A to Z to power a go kart including the battery pack and charger. When someone orders a KIT-105 or KIT-106 our technician attaches mating connectors on all of the parts and puts stickers on the connectors so you know which connectors plug together. Our technician also plugs the whole system together and tests it so we know that when you get the parts and plug them together everything will work perfectly. For a go kart you can request a foot throttle and separate key switch instead of the handlebar throttle with built-in key switch that comes with the kit. Simply order the kit by phone and let us know what parts you want, and we will special build the kit to your exact specifications at no extra charge. We will even include a free chain of any length up to 150 links with the purchase of a KIT-106 upon request.
We look forward to helping you power your go kart. Please do not hesitate to let me know if you have any further questions.