Ok 4S it is!

And for those esc I would need at least 5, as I plan to use 4wd with a drill motor for each wheel.
Also is the weapon motor able to self right the robot, and also what gear ratio is the best for both speed and power?

As for the hdpe, direct plastics can find a way of shipping to the delivery area if I contact them, I'll have to see.
In case there are problems for that, are there any alternative materials that could do the job?