Ok. Let me first preface this with something EXTREMELY IMPORTANT. You cannot simply grab a dyno graph of two different cars and expect to get 100% meaningful results. Here's why: EVERY CAR IS DIFFERENT. Some cars, even with the same exact setup simply perform better than others. These two cars in this graph are what we consider "strong cars". If they were on a bell curve, they'd be one to two standard deviations to the right of the mean.
Manufacturing tolerances allow for a variance in manufactured components. Some cars take more timing than others. Therefore, you can't assume that your car will make exactly the same amount of power. Environmental factors and fuel quality also play a huge role in horsepower production.
All that said, onto the graphs. You can see here that the Stage 1 makes more area under the curve than the Stage 2. The Stage 2 will smoke the Stage 1 on the track, but the Stage 1 will feel better on the street due to all the midrange torque it makes. The Stage 2 will benefit greatly from more displacement/built motor/higher octane fuel because you will be able to decrease the pulley size and flow more air/make more boost.
Again, if you are looking for eleventy billion horsepower, go TT and don't look back. The supercharger kit is designed for the person looking to make decent power on a daily driven/weekend track car on a budget.