Anyone know if this will work. I'm asking because I got some sprint springs for my 4th generation and I'm taking out my Intrax springs and wanted to see if it is possible to put them in my 3rd generation. what are the differences if any? Thanks in advance.

I suspect that the rear springs are not interchangeable, because of the difference in suspensions. I would check with Intrax to see if they would fit. You can also check the FSMs for the spring data.