I know I am very late to reply, but I thought I may as well. I thought my Grados sounded great already. After doing a lot of reading, I ended up buying the Fiio E10. It was like night and day, absolutely phenomenal. I appreciate the recommendation!
On an unrelated note, I found the Grados quite uncomfortable for extended periods of listening. I bought a universal headband cushion:
And I bought the flat comfy pads that come with SR60s. The change in sound was quite noticeable. I have now cut holes in them which has made the sound a little closer to the stock pads. I think the sound with stock pads is still better, however they make my ears sore within half an hour of use. So it was an acceptable compromise in my opinion.
Too bad there aren't more options for replacement (comfortable) earpads.