Hi Experts,
I have a 2005 base G35 Sedan. After around 26.5k miles on my original tires its time for a new set. Searching the wealth of information here, there appear to be many options I could go with. Apart from which tire to choose I guess the main question seems like - should I go for slightly wider tires with stock rims.
I have 215/55/17 stock tires on now, and some of the size options are 225/50/17, 235/50/17 without changing the wheels. I am wondering whether adding that extra 10/20mm in width would really make any great difference in the car handling and behavior?
Or is it more for looks? Does the size really matter? :-)

Would the handling be noticeably better than the wrong speedometer and even increased gas consumption.

I guess for real improvement in handling one has to change the rims first.

Please chime in guys

Running the 225-50-17 should be okay. There's alot more performance tires available in that size vs the 215s. The extra 10mm and 5% less tire thickness might gain you some performance. But the overriding factor that will help your handling will be the tire choice itself. The 225-50-17 won't net you jack if you run some el cheapo, no name tire.

Thanks. I thought so too. Its really the rubber you choose which matters more than the size. So if I am looking at say Yokohama AVID V4S which I believe is available in both sizes, going wider wouldnt get me much, right?

That's an all season tire? If plan on running them all year and if you get snow, I'd opt for the 215s. If it's just rainy at worst, then maybe the 225s. The thinner tire is going to be a smiggen' better for snow. Although I'd run winter tires.

these got crap snow reviews:

Good point. I am in Bay Area, so Snow is not a problem for me. Although I havent decided on Yokohamas yet, I was trying to decide which size first.

I was checking different sizes and comparing there overall diameters at http://www.miata.net/garage/tirecalc.html.
So when compared with stock sedan size of 215/55/17, speedo for
1) 225/50/17 is 1.7% fast. That is my speedo will run faster than actual.
2) 225/55/17 is 1.6% slower.

So why not go with 225/55/17 so that overal vehicle warranty wise equation becomes favorable. Why do guys not choose this size?

You won't have any issues going with the 225/55's especially in the bay area.
When you decide to buy the new tires look into the ratings on the sidewall.
Wear rating should be at least 240 but not over 340, you don't want a tire
in S.F. that has a hard compound......ya know rain....fog....wet bridges.

I went with 245-45-18's all around from the 215-55-17's and it gives a HUGE improvement when cornering. It feels almost impossible to understeer now.

The staggered width will help with high speed traction without sacrificing your turning too much, so your car will feel sturdier at higher speeds.

I have gone with Bridgestone RE960 Pole Position 225/50/17. Would update later with my feedback. For starters, its a QUIET tier... Car is pulling to the right a bit, but that could be because the new tiers may not have broken in yet (alignment is fine).