Crown Vic Tire Questions

My 1997 Crown Vic is 7 yrs old with 35k miles. The tread is less than half used , but the OEM-supplied Michelin All Season Symmetry tires show some sidewall checking/cracking, so I plan on replacing the tires.. The manual gives two size choices for these rims, the existing P215/70R 15's or P225/70R 15's. I live in coastal California, drive lightly loaded, mostly in wet, or dry , conditions, but not rarely snow, and annually cross several western and central states in longer vacation drives.. What are the pros and cons of the larger size? Are cost, ride quality, safety, traction, etc affected by these two choices of tire? Any brand favorites?