If you intend to drive in snow, get winter tires and stick them on a
separate set of steel rims.  Also, upgrading to a wider size is NOT a good
idea for driving in snow.

First off, it appears that your tires (195/60-15) are not the original size.

2000 EX 4cyl's had 195/65-15's

2000 EX V6 Coupe had 205/60-16
2000 EX V6 Sedan had 205/65-15

I assume you have the 4cyl, since the manual was not an option on the V6's.

Check out www.tirerack.com.  Lots of great info.

The stock 195/65-15's have an overall diameter of 25".
Your current 195/60-15's only have a diameter of 24.2".

Your speedo is probably off by about 3% (fast), meaning when you're speedo
says 50, you're actually going about 48.5.

You most likely have a 6" wheel width (common on 195/205 tires).  A
205/60-15 will fit a 6" wheel very nicely (24.7" diameter, and fitted for
6").  I wouldn't go up to a 215.  It's really designed for a 6.5" wheel.
You'll be "squeezing" the tire onto the wheel, and it will likely wear
quickly in the center of the tread.   And by going 20mm over stock, you
start running into potential space issues on the car, meaning your new tires
might rub against the wheel well or the suspension during turns.

Putting a 205/60-15 on will give you slightly better handling (lower
sidewall, more width), and shouldn't have any real effect on gas mileage.
And your speedo will still be off, but only about 1%.  Not enough to worry
about.

If you want to do some Plus 1 sizing, 16" wheels come it 3 widths (6.5" and
7", and very rarely 6").  A 205/55-16 is probably the best fit* (24.9"
diameter, fitted to 6.5").  A 215/55-16 will also fit (25.3" diameter,
fitted to 6.5"), but again, you may run into rubbing issues.  If you get
16's, check with the tire dealer.  They may put some 215's on it for you to
see if they fit.  You can usually tell while it's still up off the ground if
it's going to rub.  215/55-16's will give you a nice boost in cornering.
The ride may be harsher (lower sidewall), but it will be negligible on that
car.

* A quick note on the fitted size.  Tire dimensions are measured using a
particular wheel width.  The stock 195/65-15's from your car were measured
on a 6" wheel.  However, they can technically be mounted on a wheel that's
between 5.5" and 7".  Going up a wheel size (mounting your stock 6" tire on
a 6.5" wheel) is OK, but going down a size (6" mounted to 5.5") or up 2
sizes (to 7") is not advisable.  The wheel characteristics just change too
much.

This is why putting 205/60-15's (fitted for 6") on your 6" stock wheel is
OK, but putting 215/60-15's (fitted for 6.5") isn't.  And why putting
205/55-16's (fitted for 6.5") is the best choice for either 16" wheel (6.5"
or 7" width), and why the 215/55-16 (fitted for 6.5") will also work.

If you get 16's, make sure they are 6.5" or 7", not 6".  The 2000 EX V6
Coupe has 16's, but they are the rarer 6" width, and restricted to the
205/60-16 tires.  Even if a 215 will fit in the wheel well, it won't fit the
wheel itself.

Anywho, hope this helps.  I learned all of this when I decided to upgrade my
tires about 18 months ago.

Bill G
'91 Nissan Maxima SE
181,000 miles
BF Goodrich Traction T/A 225/60-15
(Yep, 20mm over stock, but they fit!)