Boy, this is one long thread to read through!
I just installed Toyo Extensa A/S in the 215/50-17 size. Toyo is offering a $70 rebate when you purchase four tires this spring
Of course the new tires are very quiet and very smooth. Time will tell. They are supposed to have an 80,000km treadwear warranty, but I won't get to worry about using it because I do my own winter/summer exchanges in my driveway (I have 205/55-16 on steel rims for winter). As long as I get close to 80,000km on these new tires I'll be happy. Perhaps a wider tire with slightly more circumference will mean that I will have more rubber that the stock size to wear off and I'll go even further! (doubt it though). The new Toyo's have a treadwear of 620 if that means anything (not really).
The diameter of the 215's compared to the winters I took off for the new tires is about an inch, or a little bit more (I didn't check, I was in a hurry to get the summers on and get going). I sure like how the 215's stick out beyond the edge of the rim, to give some protection to the rim from curbs. The wheel/tire combo just looks right. The original 205/15-17's just looked too small. They just didn't look right on that rim.
Another benefit is that my speedometer is now correct. I've always had to go about 103-104km/h on the speedo to actually be going 100km/h. Now the speedo is spot on.
What I have noticed with the taller tires is that the 5 doesn't seem quite as full of gusto when accelerating. I think the taller tires have taken a bit of eagerness out of the 5. Hopefully it will pay off with slightly better fuel economy, but I doubt it. I have been getting around 10L/100 most of the winter. Last summer I averaged around 8.5L/100km. Time will tell on this front as well.
Anyhow, the 5 seems more refined, less snarly and feisty. That's ok by me.