I am running Avon Tech M500s in 215/45x17. The Tirerack survey lists the Ride Comfort as 8.2 but it is too harsh for my taste (stock suspension). Since this is probably going to be the case with any HP stiff sidewall tire in 17" I am going to try 15s for a while. Wheels will be 15x7 and I'm looking for sizing and brand recommendations.

 

I don't know what driving conditions you experience. I have an OEM set on Continentals for sale on another thread in a 15", and you can check out Tire Rack for more info, too. I am getting Falken Azenis mounted tomorrow and know they have a stiffer sidewall, but I want to track them anyway. Some inexpensive summer UHP tires are also the Hankook R2 and the General Exclaim UHP. Tire Rack rates the General as their #1. Avon is no longer offered in a 205-50-15. If I were you, I'd do a search at www.tirerack.com on 15" tires. Good luck.

 

High Performance summer tires are not the best choice for comfort. They aren't are really good choice for 15" MINI tires.

First look at tires for the 15x7 rim.
205/55-15 is the best size for comfort and tire selection.

In High Performance All Season tires-
Michelin Pilot Exalto A/S Ride Comfort 9.0 $123 400 treadwear V speed rated
Yokohama AVID V4S Ride Comfort 8.6 $75 500 treadwear V speed rated

In Ultra High Performance All Season tires-
Bridgestone Potenza RE960AS but 195/60-15 $74 400 treadwear H speed rate. Ride Comfort 9.1, a very good balance of performance and comfort

In Ultra High Performance Summer tires-
General Exclaim UHP but in 195/55-15 $55 380 treadwear V speed rated
23.4" tire diameter is one inch smaller than stock but it's usable. Wheel gap a little more by 1/2", speedo and odometer will show slightly higher speed and miles traveled than actual. Exclaim UHP is a comfortable street tire with good value. Limited sizes for 15" wheels. You still do have the option for this tire in 215/45-17 for $73 each, it's not bad since the sidewall isn't that stiff even though 45 series. Ride comfort 8.8

In Grand Touring All Season tires
Goodyear Eagle ResponsEdge $92 each but in 195/60-15
440 treadwear H speed rated Ride Comfort 8.7
Has good traction wet or dry and good ratings for noise and treadwear
or
Bridgestone Turanza LS-V $125 each in 205/55-15
400 treadwear V speed rated. This is a closeout. Ride Comfort 8.9

Take your pick, lots of good options for more comfort.

55 series or 50 series tire will help just from a taller sidewall.
All are good street tires, even those H speed rated Grand Touring AS tires.

 

nice summary - many choices