The big 3 is because the draw from the stereo is taking away vehicle's usage based on dimming lights. This will not fix the problem, it is only a part of the BEST solution.
The OP has not yet said what vehicle they have. They have not said what alternator they have and we don't know their options. They NEED a better alternator. We don't know if they need something else besides the alternator. They COULD just go and buy a 200 amp alternator and they should be covered, (depending on the vehicle). They might be upgrading further, and want something larger, which should be planned for now. They might be able to get a OEM alt in the 140-160 amp range which would get them close enough, where they could use a cap for the rest. We don't know: their options, their plans, or their budget.
Now, lets see if you can come up with a complete thought, and actually make an effort to help. I doubt it, but go ahead and tell me where I'm wrong.
and GO