As it is so often reffered too, The Big 3 is a fairly simply upgrade. Here is WHY you might need to do it. First, lets look at the vehicles electrical system. It is a 12 volt system. This voltage is suitable, although not ideal, for running a car and all its associated electrical loads. The basic electrical system is an Alternator, and a Battery, and the devices that they operate such as lights, computer, starter, wipers radio, etc....... Most factory electrical sytems are well designed and very suitable for running the car on its daily mission hauling your butt around town. They are NOT designed for excessive electrical loads on a continual basis. Most cars use the bare minimum as far as wire goes to tranfer power from one point to another, this saves them money and helps to lighten the car. they DID NOT design the cars electrical system for your 7 billion watt amp and 78 subs in the trunk, that is the LAST thing on the auto makers mind. So what is it that needs to be done you ask? upgrade the big 3.... Lets start with the device that does all the actual work for powering up your cars electrical loads, the alternator. The alternator is the heart of the system, It is the alternators job keep the battery charged, operate ALL electrical loads on the car, and do this on a self regulating basis. Heres the first step in the upgrade. the alternator CHARGING wire. This is the wire that goes from the alternators output, to the positve battery terminal, It is THIS WIRE, and THIS WIRE alone that RUNS YOUR ENTIRE CAR!!!! Now look at the wire under your hood, it comes off the back of the alternator case, attached by a bolt and usually a protective cover. How big is that wire?? Not very big at all is it!! Alot of them are only 10 gauge!!! that 10 ga. wire is what runs your car, AND the big bad stereo pulling all kinds of current!!! This is the first wire that needs attention from you. Typically an 8 ga. wire is sufficient to allow the alternator to put out its full potential, although alot of people use 4 ga. or larger....... You need to run the new wire from the alternator directly to the positive battery post. It needs to be run in a safe manner so as not to rub on belts, have enough length to allow for engine rotaion and movement, and again, as safe as possible....I typically find a good path to run the wire, crimp AND solder the correct terminals to each end, heat shrink them, then DOUBLE LOOM the wire as a final step to ensure no future issues or problems. And NO, dont fuse this wire, its a waste of time and a waste of money to do so, besides it would require TWO fuses to properly do it, and thats just not practical or needed. Once this wire is installed, you alternator is going to be allowed to do ALL tht it can possibly do to keep your cars electrcial system up to par!!! Moving on we come to the battery, that big heavy ugly thing that stores our electrcity. The battery is there for one real reason, that is to start your car. its not there to "make" power for your stereo!!! Yes, the battery also does one other important thing, It also supplies power to the elecrical loads of the car to keep them going when electrcial loads are HIGH and current output from the alternator is LOW, like when its cold at nigh, raining, you have the heater on full blast the wipers on the head lights on the defrogger on, the stereo on, the neon light going, and even your GF has her sex toy plugged into the ciggarette lighter. ALL while sitting at a stoplight with the engine running at idle and the alt. is kicking out a mere small fration of its available output! The battery is an important part of your stereo though, THE BATTERY is what supplies the PEAK SHORT TERM curent demands to your amp. So guess what, you need to upgrade it also......... Simple enough, here we want to use at least 4 ga. wire. " Where do I want to put it" you may ask yourself????? Here is where the grounds come in. the battery needs to be properly connected to the chassis of the vehicle. AND to the engine of the vehicle. The ground Is JUST as importatn as the positive power leads. And FYI, Current flows from negative TO positive by the way.... So first step is to go from the battery neg. to the chassis/body...Try to keep the run as short as practical. Find a good existing bolt in the car, or drill a hole and make your own connection, but either way, be sure to grind the area of attachment down to bare, shiny metal. try and use a bolt that is at least 1/2 inch in diameter..... be sure to paint the connection so as to prevent rust. next step is the ground from the battery to the engine block. same rules apply here as they do to the alternator wire, EXCEPT all the protection stuff, if this wire shorts out, NOTHING bad will happen! Simply find a good attachment point to the block, using something like a alternator bracket bolt, engine lift point bolt, etc....again, be sure the metal is clean and shiny.... Congrats dude, you just upgraded your "Big 3" The idea of all this is to allow the battery and alternator to do ALL that they possibly can to supply your audio system with as much current as it needs. this technique will work on a majority of cars that have a nice system in them. If you are pushing some SERIOUS wattage and pulling some MAJOR current, Other things will need to be done to your cars electrcial system. Well, I think i covered everything, did I forget anything???