Crossfires DO NOT have progressive springs. They do not have tapered ends either. When you cut the spring it sits in the mount just as it did before. Obviously you will have less suspension travel because your spring is shorter, but even if you buy aftermarket springs you have same issue. My car is not "darty". As far as alignment, It's only been done for about a week or two, so I cannot answer that question.
Most car suspensions are basically the same and work on the same basic principals. Remember, back in the day, hot rodders were the ones that were not afraid to try these things. That is why we now have shows like SEMA. You don't have to be a nuclear engineer to be able to work on your car. If it makes you feel better, buy some after market springs and put them on. I for one, am perfectally comfortable cutting mine. Thanks to guys like BRIANBRAVE for paving the way.