Problems with 215s
Tire Rack told me I could go with 205/50, 215/50, or 225/45. I only wanted a little more width to keep the rims from scuffing as they really stick out (see first picture):
I got the Kumho ECSTA ASX 215/50s from Sears for $86 a piece. Once on I took them for Napa hill ride...
Here is a great YouTube video of a track race between the Honda Stream, the Mazda Premacy (Mazda5), the Honda Odyssey, and the Mazda MPV. Make your own judgement on which is best.
http://youtube.com/watch?v=zU4paH8qcQ8