Ree,
The Hotchkis / Airlift bags come with a set of heat shields that go around the exhuast pipe to prevent this..
That said however I've never had mine installed, but am concerned enough about it to send out my new Dynomax 2.5" rear pipes out to have them Cermachromed, not for the looks but to cut down on the heat transfer...
You could try what I'm doing or I suppose you could wrap the pipes near your springs with Header Tape to cut down on the heat. Just a thought.
L8R