Are you planning on taking your car to a race track?
If we are talking about tires and handling, the order of importance is generally as follows:
- Tire compound
- Tire width
- Tire construction (e.g. sidewall stiffness)
- Wheel width
This is why race cars (real ones you see on TV) use tires that are worn out after 40 minutes of driving. They have extremely soft compounds compared to street tires. This is why tire compounds are almost always prescribed in the rules. This is why there are tire width limits in the rules and there are more rule sets with tire width limits than there are with wheel width limits.
Wheel width is #4 on the list. It makes sense to talk about optimizing wheel width after the first three items having to do with tires have been accounted for. I track Miatas and for best performance use 225 width tires on 9" wheels. But, the tires are the most important component by far. A race 225 width tire on a 6" wheel will perform better than a street 225 width tire on 7" or 8" or 9" wheel, or a street 245 width tire for that matter (if the car has enough horsepower).
(On a side note, the current generally accepted wisdom in the performance driving community is that for best performance the wheel should be slightly wider than the tread width (not section width) of the tire, with the sidewall of the tire ideally perpendicular to road surface. If you look at the various race cars across the disciplines you'll see many examples of this. But street cars generally have tires wider than wheels, and more section width than tread width, so that the wheels are not damaged against curbs and tires don't hit fender liners when cars are loaded with groceries to the max.)
For street driving in a family car, I doubt you'll be able to tell the difference between 1" of wheel width either way. Possibly even 2".
Street cars are used in a wide variety of conditions. Consider:
- Driving in spring/fall with snow tires on (very soft sidewalls).
- Driving on worn out tires in wet conditions.
In both of these circumstances, what wheel you have the tires mounted on absolutely does not matter.
Another consideration that matters a lot in street driving and not so much in track driving is rated load carrying capacity.
- Wider tires support more load
- Taller sidewalls support more load
- Taller sidewalls make the vehicle less responsive
If you are considering getting narrower than OEM tires in particular, make sure they are rated to support the rated maximum gross weight of your vehicle. One issue with large diameter aftermarket wheels is the tires that fit them and the vehicle aren't rated to support the OEM max gross weight.