It totally depends on whether the woofers are high-efficiency (needs low power from amp) or low -efficiency (needs considerable power from the amp)
I do not know a way to tell just from looking at the speakers unless the minimum power requirement is on a label somewhere. Can you check with your local audio shop?
The size breaker you use is determined by the size wire used in the circuit. If you use AWG #12/2 wire then use a 20 amp breaker. If you use AWG # 14/2 then use a 15 amp breaker.
You use the correct size breaker depending on the size wire in the circuit. If the circuit is wired with AWG #12 wire use a 20 amp breaker. If it is wired with AWG #14 wire then use a 15 amp breaker.
25 amp breaker
if you want to use your stock head unit to run your subwoofers you can go to any car audio shop and buy a converter that will splice into your rear speakers and convert the signal to use the RCA cables for your amp.
70 amp
You should use 14 AWG wiring on all 15 amp circuits.
im have a 30 kva transformer 3 phase 480v 80 amp panel 120v what size disconnect should I use
No, if you read online you can do it yourself.
Depending on the desired sound quality and the size of your car, your best bet would be to stick with 10" or 12" Subwoofers as these would take up a moderate amount of space and offer lower frequency response (i.e. deeper bass) than 8" or 6.5" subwoofers. Pay close attention to the maximum RMS wattage and the size of the magnet (bigger is better).
If the computer is moden then use 5 amp and if the computer is older and smaller then use a 3 amp
Don't use aluminum wire inside the house.
15 amp