here's my take on it:
- motor okay
although personally I'd go with an outrunner and a motor mount. cost will probably be similar, but if something breaks you can exchange it quicker, you have more power on hand and you can customize gearing. being able to tweak torque and top speed depending on what you feel like doing is quite nice imo. drawback
- battery okay
- speed controller great choice
- remote: ditch the enertion remote. overpriced and enertion sucks (personal opinion as an ex-customer).
if you wanna get a cheap remote that is the same you'd get from torqueboards, go for this one
it's even the newer version with better throttle and and a different antenna for better range.
- charger is fine
- charger bank is fine
- charger splitter is fine (or skip it and just charge them separately
- motor extensions are fine
looks alright. make sure you get all the necessary connectors and stuff. maybe loop key for on/off. but other than that, you should be fine.
tl;dr: think about your motor choice (not that there's anything wrong with it!) and definitely reconsider buying that overpriced remote controller from enertion.