Difference between Sony DVD-RW discs?

[jondunn3]

I'm looking to purchase a spindle of 25 Sony DVD-RW discs but wondered if anyone knows the difference between ones in red, purple and yellow packaging?  Also, some have a model number of 25DMW47ASP whereas I've seen identical looking ones with the model number 25DMW47SP or 25DMW47SPM.

Any help would be much appreciated!!!