Well, I've never started a thread before, but I'm looking for comments and opinions from all youse guys on my question and I hope this is the right way to solicit them.
I have been a tire upgrader my whole life, buying slightly wider and taller rubber for each car I've owned. Now it's my daily driver BRZ whose OE rubber is wearing down to the point that I would be nervous facing the rainy/snowy season without new shoes on him to be sure he goes where I point him. While many of you scoff at the Primacies as "Prius tires," I'm certain the designers have chosen the 215/45 as the size that maximizes traction, handling, economy, etc.
Nonetheless, I have found in the past that moving from 195 to 225, for example, has a very nice effect on ride and other qualities, as long as they fit, and I've become adept at calculating in my head the difference between speedo and actual speed (we call that "bistro math" around here). I have enjoyed the Conti Extreme Contact DWS recently on my previous car, am looking for a Performance All Season tire, and would consider even the 245/40 some of you have used -- do you need spacers for that size, or what.
So, I'm sure there's lots of wisdom out there. Please fire away.