I'm working on getting 17" wheels with new tires, so I thought I would make a quick post with my experience with the lousy stock 225 65 16's. As some have said, these tires leave much to be desired. However, after some experimentation, I found they worked much better with increased tire pressure (over the factory recommended 35 psi). I have run mine at around 41 psi in the front for more than 6 months and have found the handling and wear to be better (probably the MPG, too). The ride is only slightly harsher. I ended up increasing the rears to around 37 psi. Increasing the rears more than that only worsened the ride with no noticeable benefit.

This might not work well for everyone (carrying more weight in back, might need more pressure-live where the roads have huge craters or frost heaves, ride might be too harsh-etc.) For my lightly loaded (90+% of the time) Quest and on my smooth roads in Virginia these pressures work well. Use at your own risk, and all that jazz.