What a neat car!
 

Just got my new Elantra Touring in April. I really like it. It has the option package with the 17 inch wheels, they really look good. I think the tires are the cause of a "hard" feel to the ride. I feel EVERY bump and crack in the road. I've read that the General Altimax HP is a much smoother riding tire than the Kumho Solus OEM tires, but I'll wait awhile before deciding to change them. The only problem I've noticed is that the radio is intermittent when I hit bumps/cracks WHEN THE CAR IS HOT FROM SITTING IN THE HOT SUN. It isn't that way in the cool of the morning. I can smack the dash near the radio, when it's being intermittent, and make it intermittent each time I smack it. I figure there's something loose or not fully connected at the back of the radio. I'll ask my dealer to remove the radio and remove all plugs/connections, reconnect, and reinstall. If that doesn't fix it, then it's an internal radio problem requiring a replacement. My dealer is also a Nissan dealer, they have a great service department, and this is the third vehicle I've bought from them, so I think they'll be willing to do this.

Sounds like a nice car. I've seen this as a common complaint on this forum and forums of other makes. People go with a larger, upscale wheel and tire option and then realize the ride is much stiffer than they expected. Folks don't realize that the lower aspect ratio of tire (50 or 55) is going to have a stiffer sidewall compared to aspect ratio of 60 or 70. In some case, the sidewalls are much stiffer than it seems they need to be. The 17" Michelin OEM tires used on the Hyundai sedan models are notorious for this. Yes, there is a difference in ride among tire brands and models and you can improve the ride, but as a rule the lower aspect ratio tire is going to give a stiffer ride.

Could be a loose harness connector on the back, or a cracked circuit board or connection inside the radio itself. I'd suggest you talk to the dealer about replacing the radio. I'm not sure how closely you've read your warranty documentation, but it covers anything going wrong on the car during the first 12 months. If the dealer is reliable, I am guessing they will do this anyway without you asking when you describe the problem.

Good luck.

Better ride
 

I just got a Touring with 16" tires. I think the Hankook tires ride very smooth over small bumps. However potholes are very jarring. That would be a suspension issue I guess, might upgrade shocks at some point. I liked the looks of 17" rims but I had a Nissan with sunroof before and never used it so opted not to pay extra $1500. From OP experience that may have been a good decision.