RS2 and RS1 are also Grado´s offcourse, but have a pretty different presentation then SR225!
I replied your pm about the SR225, and yes that´s a great great starter pair of headphones, but RS1 and RS2 are a class higher, IMHO.
Must admit, being a Grado lover, RS1i is still one of the nicest sounding headphones my ears listened to, RS2(i) comes closer then many think.
So, RS2 over SR225, offcourse! :)