I recentyly purchased a battery but while changing it out for my old one i noticed that it is not rated as high as my old one (CCA, RC, and AHR); it works great right now, but b/c it is not as powerful as the last one should i replace it with a more powerful one, i live in chicago and will have a pretty cold winter.....any info would be great. thanks reed

How much of a difference are you talking about? You should be fine as long as your starter isn't too old and the new battery is of the right series.