The Sprint springs will handle about the same as any other coil spring - Eibach, Hotchkis, etc. The Sprints are VERY popular because they are the lowest springs available for our cars. I would recommend a good lowered shock but you should be fine with those that you have now. As far as springs falling out of the rear during driving I have NEVER heard of this happening. I would be one of the 1st to hear about it.
Jason - Street Trends