[mikegett]

No. The altenator won't automaticaly displace 200 amps. If there is not enough pull from the battery, it may only put out 45 to 50. 200 is the number that the alt can produce. Before purchasing a new one, you should concider upgrading your battery to altenator power and ground wire. Do a search for the big three. Even if you need the added altenator, you won't get the benefit without doing this. Your current wiring will bottleneck the current going to the battery and could cause more harm to the new altenator. It is the same thing as your power and ground wire to the amp. Your system will always pull 12 to 14 volts but if the wire or ground connection is poor the amps will go up. Your new altenator may pull more amps (and die sooner) than what it would with new wires. This is a fairly cheap thing to do. Have a autoplace test your current amp draw on your car. Do the big three and then have it tested again. You may be suprised and find out that you lowered your amperage pull and won't need the new altenator. The other thing to check is that your ground posts (on the battery and on the amp ground) are as large as possible. You may have a 4 gauge ground but if your posts are too small the system will pull excessive amperage. I use a distribution block for my ground that is two inches square to ensure full contact with the metal. If you have done all of this and your car still tests high on the amperage pull (have it tested, don't go by assuming rms or max system wattage) then upgrade your altenator. The last thing you want to do is pay for something you don't need. By the way. I have had my share of large systems. Never have I owned a car that needed a altenator upgrade beyond 105 amps. Your system wires, grounds, battery life, and altenator lifespan have a much larger impact than the max amperage your alt can produce.
You stated that your car is " stock alt now, pushing 1000 watts 2 3 12s, adding another 525 ". Are you going by max or rms watts? Neither one mean anything to your cars altenator. It is easy to hear that a individual has two 1000 watt rms subs with a amp to match it. This does not mean that the system is seeing 200 watts continuously. The amp rms is the max wattage that the amp can produce continuously without clipping. This is only seen when the amp input has achieved its max input value. Look on the gain setting. You will see something like .2 to 8 volts or whatever its spec is. Only at the max value will the amp produce a continuous rms wattage. On a properly set up system that will be at your max volume that you listen to. If you setup the gains too high so that the amp sees the max input at half volume, then it will begin to clip continuously. You won't get added usable wattage. ONLY wattage that contains distortion and kills speakers and amps. I appologize if this seems confusing. There are alot of factors that contribute to your cars final wattage. You will hear from many people that they have systems pushing 1000 to 2000 watts continuously. In reality, most of those systems have the potential but only reach it at peak volumes. The only way to know how much you continuously draw in watts or amps is to place a meter on it.