Your Caddilac has a pretty decent large case alternator on it from the factory, so it will cope with the load better than many vehicles. You will still have a fair amount of voltage drop with the 2200, but it's not like it's going to shut the car down.
We have a very reasonable priced (inside your price range) adjustable voltage 250 amp unit that is a direct bolt in for your vehicle. We could actually set the starting voltage to 15.3V, so that at full temperature you would be closer to 14.9V to start with, which would keep your entire system voltage much higher. This is great for the caddilacs, as they have low voltage to start with. You will find that power windows roll up faster, lights are brighter, and your amps will much more efficient. Holler if you want any other specs.