alternator output 92 civic

Hey,
i have a 92 civic lx 4dr
i'm going to be puting another amp in and i'm wondering if i will be drawing too much from my alternator

currently i have a kenwood mono amp running a 10"
it's specs show that it draws 15amps
i'm looking at adding a 4channel pretty soon
about the average i've seen for specs on some amps i'm looking at is around 35 to 40 amps

my question is if a stock civic alternator can put out 50 - 55 amps without messing up any of the other electrical systems

i've heard that you are supposed to estimate your alternators reserve as being 40% of it's total capacity
this would mean that my alternator has to have a capacity of around 125 amps in order for me to run those two amps

any help or advice would be appreciated
thanks
Sean

get your current one rewound, and you might wanna add another battery to the trunk....