The other "difference" with the 325 is you get a leather headband. If you want leather in your eventual build, you'll have to spend $40-$60 for a leather headband if you buy the 225. I eventually traded up from the 225 to used MS2 because I wanted to remove some vinyl and plastic from my life. The 225s sound great and are lighter (more comfortable) than the 325.
I'd agree with this, but if all you want is the drivers, the SR-225 are a great buy - if you plan to re-use parts (like the headband, gimbals, etc) the SR-325 make some more sense certainly. I'm just not seeing the point in spending an extra $100 for stuff that would go in the trash.
The RS2i don't get enough love because the RS1i is objectively better - bigger cups = bigger sound. The RS1i also changes the plastic gimbals for nice metal ones, which account for a good portion of the $200 premium. If price is not the object then the RS1s are more better.
This. I will say I haven't heard the RS-2, but just the build quality point is worth considering. I remember devouringone (speaking of which - where'd he go?) making a point about the woodworking on the RS-2 being of lesser quality than the RS-1 or GS-1000 as well (I do not know if this is true, but basically everything else on the RS-1 is superior to the rest of the Grado line (GS/PS1k excluded), so it makes enough sense.
This is a good point martin - that second-guessing problem can absolutely ruin a purchase!