What size power and ground wires do you need for an amplifier?
Using thicker power and ground cables will allow your amplifier to draw the juice it needs from the battery more easily.
Before you can decide on the appropriate gauge wire for your installation needs, you need to figure out the current demand of your system. To do that, you must ascertain the approximate current draw (in amperes) of your amplifier (or amplifiers). First, calculate the total power of each amp (multiply the number of channels by the number of RMS watts per channel). If you have multiple amps, add up the total power figures to arrive at a grand total.
Second, double your grand total power figure. And, finally, divide by 13.8 — the result is your system's approximate current draw in amperes. Cross-reference with the cable length (the distance from your battery to the amp mounting location) to determine which gauge of cable you need.
That should help you out with the wire sizing...
As for crimping, well, there are a lot of options. Best would be to visit a local Electrical Supply house once you've selected your cable and then get the right tool and tabs for the cable. There are also some nice terminal blocks for batteries too with better connections.
How the car operates? You mean will the load of the system have any effect? Well that all depends, Capacitors can be added to help and yeah, HO Alternators for crazy systems are a must. Without specifics, it's all just assumptions.
