I speak to you as fellow Gradophile and not a person who builds cables:
They sound good but the problem is that they're usually associated with other mods while you've got them open so it's hard to pinpoint what does what exactly for a lot of these modified cans.
It doesn't do anything for the bass thats worth the investment, it cleans up some of that "sparkle" in the treble, how much that improves really varies upon materials, how your cans were built, and your hearing perception/taste, but the midrange in my experience at least, as a Gradophile, definitely becomes livelier, warmer, and you really get that last 5 percent of detail retrieval.
Never in a million years would any sort of mod make these headphones neutral so it won't cure anything, but there are things you can do to improve on the low end, but considering you have an RS-2 you probably have quite a bit of that already.
Cables are an interesting topic of discussion, we have all the people who like to bring up anti-cable threads, but then we have Grado who improve upon their lower end models with nothing but a cable sometimes.
You have a lot of options with materials, who builds them, sheathing, but for the most part I prefer a nice 4-conductor cable over a tightly braided 8-conductor. Grado uses the same gauge wire for their 4 and 8 hence the thicker, more robust cable.