I have a 2003 model but that doesn't mean I had them since 2003, I had them since 2009 and bought it used. Burn-in does not make a big difference, it's a non factor to me. It will not suddenly just transform into something different after a certain amount of hours usage and it is arguable that burn-in is placebo since from all the frequency graphs I've seen show that the FR does not change after hundreds of hours. If you read my post, I said I heard a RS1i at store that is just as bright against my 2003 RS1 then I proceeded to look for a used pair of RS1i from these forums only to find out there are massive variations. As far as I know, the only "dark" sounding model should be the HF2. The HP series were made by Joe, John has always gone with the bright route and not the neutral route. Wiki is not a reliable source, I don't ever recall Grado wanting to tailor a sound that is more suitable towards the mass public who complained about it being to bright. There's always people who like bright headphones, so why should Grado to switch to a darker sound? I don't recall Grado listening to complaints. I always see alot of people complaining about how they are uncomfortable and how their technology is old yet why doesn't Grado change that? I doubt Grado listens to complaints. The whole switch to a darker sound is bogus, the new prestige series still have a bright sound.