wheel sizes

You'll probably want to keep the tire diameter the same when you go to the 14" wheels. The 14" will simply use a slightly lower profile tire than the 13". What is on the car now, a 7.00-13? That's listed as being 25.2" diameter. A 205/70-14 is 25.3", a 195/75-14 is 25.5". Either one is close enough.