My opinion is, although the G-cush pads make the can a little more comfortable (not a lot), they also make them sound immensely worse. What people think is an addition to the soundstage depth is really just an empty and hollow feeling that gets added to the sonics because the pads do push the drivers slightly away from your ears. I think it also adds reverberation to the sonics which is just bad news in my book.
I agree on this about the (G) cushions with the 325's.
You also lose all of the intimacy/impact of the sound signature, and the comfort between the (L)/(G) cushions is not all that of a big difference. As a matter of fact I found the (G) cushion a little warm on the ears after some time. Grado puts a lot of R&D in their design…I'm sure thats why the 325's come with the (L) cushions, where as the GS/PS come with the (G) cushions. I'm saying this from my experience with the GS1Ki's, which are made for the (G) cushions. Just my opinion.