My opinion on Grados is that there's very little reason to get anything more than the SR60i with Lcush pads. I don't think spending another $220 to go to the top of the prestige line increases the sound quality in a way that makes it worth while. I did it just to compare and found it to be pretty much too similar. It doesn't mean they're bad, it just means the SR60i is that good even though it's the base model. SR60i with Lcush new runs $100 basically. It's an excellent headphone. I personally felt like the SR325i was not much of an upgrade. It had slightly smoother sound, a wee bit less congestion, but ultimately, didn't sound like $300 compared to $100 to me. Sounded like a miniscule, very small, difference that could have even simply been manufacture difference. I just chalk it up to the housing of the drivers. I'd get the SR60i's and later get a wood enclosure for them. The SR60 drivers are excellent.
Very best,