need a brushless medusa motor

[rat]

hi lads..its prolly been asked before, and i know most are probably sick of answering these questions..i need a new motor for my hyper st pro..

definatly going with medusa, but which one??

vehicle weighs 10.2 without a motor..

36/70/????kv...

36/80/????kv...

im after speeds of 40-60 mph, but want a cool running setup..

im useing 6s/5000mah/20-30c ,mmm esc .

any help appreciated..