Wellcome to the Forum.
I'm somewhat new myself. Only had my Yaris for about 2 month. If you manage to find a side molding for the Yaris, l'd like to know about it, It's something that might become usefull once my car gets older. Simply to take away from the dings and scratches that the car is going to accumilate and to prevent new ones.
The 205/50/15 tire size is about the same diameter as the stock 175/65/14. Personaly, I'd go with the 195/55/15 which is about 2% bigger (in diameter) then the stock, but the 55 series would return a more comfy ride the the low profile tire. However, if you plan on installing performance springs, the 50 series tire (low profile) would be a better fit to capalize on the tigher suspension.