I actually haven't heard the 225s, my knowledge of them comes from research only. I would doubt that the sound stage is much different because there's not a huge difference in that department between my 325s and 80s. I've heard many people say that there is very little difference between the 225s and 325s, to the point where some coulnd't justify the price difference. I wanted to go to the top of the Prestige line though, which is why I went with the 3s....I think you'd probably just have a slight bit more refinement in the 3s, and they also might be a tad more bright than the 225s are. I think most people consider the 225s to be the sweet spot in the line, though, in terms of value.
The biggest difference I notice between the 80s and 325s is the layering of the sound stage. They both image exceptionally well, and the overall size of the sound stage is similar in both, but I find the 325s to have a bit more delineation and separation among instruments, and I also feel that the presentation is a tad bit more layered, which I like. I would expect the 225s to be pretty similar to the 3s in those areas, though. But I don't think you'd notice a difference in the overall size of the sound stage.
I'm sure others who have heard both will chime in and be more specific, but if you're wondering if an upgrade to the 3s is worth it, I'd highly doubt it. You'd probably be better off moving up to the RS1 or PS500s.
EDIT: Never mind, I see you already have the RS1s....lol