Wha? The SR325is's highs? They were the most fatiguing painful headphones (not just Grado) that I've had on my head. YMMV of course, but thinking of the SR325s still has the hairs on the back of my neck stand up at attention. I owned them for a month and ditched them for the RS1s and never looked back. Sounds like your RS1is had "issues" or needed burn-in?
For those who think the RS1s have too much treble energy, then the PS500s would definitely be the way to go.
I heard that the RS1s has a slight difference in sound sig. than the RS1i.... Have you tried the RS1i for more than 8 hours?
I prefer the 325is than the RS1i if running without amp.
Edited by Awgd8 - 10/31/12 at 7:25pm