See this thread:
ex35-replacement-tires-t562094.html
It has a good amount of information about what others have tried for the 225/60R17 tires.
For what it's worth, I'm running the Primacy MXV4, 235/55R17 99H. They have a diameter that is slightly smaller than the OEM size, but I have not experienced any issues with the speedometer or electronics.
Since you're still under warranty, I would suggest to stick with the OEM size for now (which pretty much means getting a different brand). If you're not interested in fitting a less sporty tire, I can't picture you getting something with a lower speed rating like I did.