Re: Help in buying new tires!
A 205/60 would be a good option to increase the tire width a bit (10%). Your speedometer will only be off by a little so don't need to worry about that.
Getting a good tire that is more performance oriented is going to give you better results over changing the size. So a long with going with the wider 205 I would go for a more aggressive street tire for better performance.
What's your budget? Type of weather in your area? Have you considered running 2 sets of tires?