the big 3 is a good upgrade for the car to the battery, 1 it will imporve ur chargin with a thick ass cable 4guage or larger from the battery pos to alternator, 2 it will make a bettery ground to the car, from the battery neg to chassi, and 3 it makes another good ground to ur engine to the battery neg post, use the largest cable to achieve the best big 3, mostly a 4 guage wires to everything is fine, but the larger guage is better, and if u did a big 3, some people dont bother usin caps on there amps since this upgrade provide better power flowin. hope this will help, i am thinkin of doin this wen im gona do a big setup in my car hehehe