Mini 8ight new esc and motor

[Wupding]

Bought my mini 8 last year and has since been sat idle until the winter to move indoors.... going to upgrade my servo to the savox as stated in the previous thread.

My question is how does the kv system work compared to the normal 'turn' brushless system work... ie a 5.5t is a lot quicker than a 13.5t

What are my options in buying a new esc and motor? I don't want to start hacking away at my chassis like i have seen in some pics.

I would like something that still falls into the brca regulations so if i decide to run some regionals etc i can do that

Thanks in advance for your help