AoA bro. What about the next step? Have you taken it? Here are the official sizes I have found from Yaris World website:
WHEEL BOLT PATTERN PCD = 4 x 100mm
CENTRE BORE = 54.1mm
OEM wheel sizes, offsets (ET), and tyre sizes (diameter in inches):
14x5, ET45, 175/65/14 = 23.0
15x5.5, ET45, 185/60/15 = 23.7
16x6, ET51, 195/50/16 = 23.7
17x6.5, ET51, 205/45/17 = 24.3
TRD Option 18x7.5, ET42, 215/35/18 = 23.9
With stock suspension, you may safely fit many tyres from 23.0 to 24.3, +/-3%.
Check this page:
Official YARIS Wheel & Tire Guide - Toyota Yaris Forums - Ultimate Yaris Enthusiast Site
What do you people say?