Little modification will be required to fit these tail lights, as the wiring grips are different on both tail lights. Please don't cut your original wiring grips.. do a little search on Yaris-world forum. you may get your answer from there.
Do a little search on the rear bumper size of RS model. there might be difference in them.. same happened with me, when i was installing Second gen Rs tail lights on my 2008 Vitz.. fitment of the light was perfect with the car body, but not with the bumper.. due to which i returned the tails lights, as RS bumper were also needed for perfect fitment.