it depends on the class your trying to run in. for stock, people are running the biggest lipos they can get to keep the voltage higher for longer. for modified ive heard it doesnt really matter as much so you can build the car for weight/balance ect, but you have so much horsepower weight isnt such a big deal. in canada and a belive the us too, min weight is 1380 for tc classes. depends a lot on the equipment you want to run. my hobbywing stuff seems to be on the heavy side and i like bright white backed colors, so 1390-1420 grams is my norm.