My 2004 Monte Carlo SS runs loud and it never did before. It's loud at low and high speeds, but seems to sound worse at low speeds. I do need a front end alignment (the car drifts to the left); would this affect the car to cause the loud running engine?

That depends on if you think the noise is coming from the motor, or the actual road noise that comes with driving , its probably the same at both speeds but sine you have less air and outside noise,, you hear it more at lower speeds. does it make the same noise when started but not moving? if you answer that yes, then its something else besides road noise, if it is no, then get your front end checked, it could be anything from a bad alignment to a bad wheel bearing, or bad brake ,