Regarding ferday's post, I'm sorry to hear that you can't easily demo Grados because I also live in Canada, and I have access to any Grado model I want. To answer your SR80i upgrade question, think that the SR225i, and the RS1i, would be my two suggestions at different price points as an upgrade to the 80i. I know that you like the SR80i's sound signature, I do too,, I think that they're great headphones, especially at their low price, but if you have the chance, try to demo the PS500 or the GS/PS1000, you might end up preferring one of them's sound signature, I know I do.
Thanks! I make it to Montreal a few times a year so maybe ill check some out, what's a good shop?