I am really happy with my new tire setup on my OEM Nismo wheels. I wanted a meatier looking tire while still maintaining the overall diameter of the factory tires.
Reasons to install wider tires:
-They last longer; The more rubber you have contacting the road, the less
weight per square inch on the tire compound, meaning less heat/less wearing.
-They look better; This is an opinion I know, and some people like stretched
looking tires, some with their drops and camber angles don't have a choice,
but for stock ride height, I really like to look.
-They ride smoother; This could be a bad thing for some people, but I really
like the fact that running over reflectors on the road or manhole covers
doesn't bother me anymore, no loud noise and no harsh jerk in the steering
wheel. This setup is much wider than a factory 370Z, and much, much wider
than a regular car, meaning all the small potholes on the roads you can
now hover over without your tire digging into them as it does on a
normal 215 or so sized tire. Also, I have not noticed a road noise increase at
all.
-An inexpensive mod, since you are not required to buy four tires, but just two
rears; I moved my rear 285/35R19s to the front wheels, I was getting
a lot of camber wear on them and needed to change them soon, but instead
of replacing them, I decided to put them in the front where factory height and
alignment has virtually no camber, this meant that now I can start running on
the outside edge of my rear tires where I still had plenty of rubber to wear. I
can now get at least another year out of the otherwise worn out tires, this
made my total MOD cost under $500, and with brand new 325s in the back, I
can't complain.
Possible Cons:
-The biggest one people talk about is gas mileage, first, this is a sports car
and I'm sure a very slight increase in fuel consumption won't bother most
people on this forum, and second, I really have not noticed a difference in
MPG.
-More road noise; honestly, I felt like my car got quieter with my new setup
but I definitely believe that road noise has more to do with the type of tire
(Manufacturer, compound material, tread pattern, tread depth, air pressure,
type of road you drive on, ect.) than it's size. Road noise has not increased
for me.
-More cost; sure in general larger tires cost more money but our cars already
take pretty large tires and the price difference isn't so big. In many cases it
depends on the deal you are going to find more than the tires size per say. I
for example got really lucky with size 325/30R19 because I found that size tire
for much less than any tire from 275 and up. Discount tire had Cooper Zeon
RS-3Ss for $181 a piece, every other tire that size was nearly double.
(Discount Tire doesn't have it on their site, but in the store they can lookup
tons more tires than the ones on their website). So again, it depends on what
deal you find but sometimes they could end up costing even less, like in my
case.
-Steering Response/Handling; Response is still sharp and the car behaves
much the same as it did with factory sizes. I do feel a slight bit more
floatiness over large bumps/humps in the road but it does take them much
smoother, which I really like. Steering response however is still just as sharp.
As you will see from the pictures, I have no spacers anywhere and the rear tire is completely flush with the fender, the fronts have about 5mm to go in order to be flush but overall it's a very flush look without any modifications. I have absolutely no rubbing issues whatsoever, not when hitting bumps, not when turning full lock to full lock.
I would recommend this mod for Sport Package Wheels as well, moving the 275s in the front and getting 305s for the rear (Discount tire says that according to their system, even the sport package Z can take 325s in the back, although I don't know if that will be going too far or not). Base model wheels can also have their 245s moved to the front and 275/40R18s installed in the rear.
Attached with the pictures are also results from a tire size calculator, comparing old front tire size with new tire size, and old rear tire size with new rear tire size. As you can see, those tires are the closes to OEM diameter you can get, staying within less than 1% of the original overall diameter.