[Oppressor]

That totally depend on what he want to do.

With a MMM, it would sure be better to attempt speed run on 6s instead of 4s.

For racing, yeah most place probably ask for 4s.

On a pure price basis 6s 5000 mah is pretty much the same price than 4s 8000 mah and 1/15 more energy isn't much energy difference in favor of the 4s lipo.

So i still stand on my previous advice. 6s if there is no rules forbidding you to run it(racing).