I am going to be installing a new system in my car probably at the end of the week:
2 Audiobahn 10" natural sound DVC (4 ohm) subs
Audiobahn 1200 watt amp
stock speakers

Will my stock 105 amp alternator have a problem keeping up with this? I'm not the type to have the system really loud CONSTANTLY, so it would only be loud on a very sporadic basis.

Thanks.

you should be ok i would think, whats the fuse size in your amp?

Its either 60 or 80 amps I think...tell you the truth, the amp installation kit that I ordered didn't say the size, but thats what I saw in other 4 gauge kits

no the fuse size in the amp itself

Oh...yeah, sorry about that. Actually, even looking through information online about the amp I can't find that. Maybe (since you seem to know a lot more than me and might have other sources of information) the model number of the amp will help:
Audiobahn #A2150HCQ
Thanks.

well it claims to put out 1200 watts @ 1ohm which i highly doubt it will do but nontheless most amps in that range will have a max current draw of 100-125 amps.

so you'll definitely want to upgrade your magic three wires under the hood, and probably get your stock alt re-wound for higher output. Or you could buy a new one if you get a good deal, id say something around the 150 amp range should do the trick. And make sure your starter battery is well charged and reliable.

of course if you're hurting for money a bit (like most of us) you can run your stock alt with the amp and just throw a battery charger on it every night. That way your car probably wont die during the day, but your alt will still fry eventually.