Possible brushless setup (your thoughts)

if you go with a 6s setup choose a motor that will get you a max motor speed of 35k and this will give you a better run time than a 4s 2200/2260kv setup so you can afford to run a smaller pack. One advantage that the 6s setup has over the 4s is it will run cooler, if you live in a hot climate this will be an issue