As the others have said, you lose the inboard armrests. But that actually gives a little more room to climb through the middle to the 3rd row when the 8th seat is not installed.
My original plan was to leave the 8th seat in the garage and only install it when we needed it. But my 3 kids actually prefer all sitting in the 2nd row when we're just driving around town. When there's only 1 or 2 kids in the car, the 8th seatback is folded, so they get an armrest and cup holders. When the 3rd kid is with us, they unfold the seatback and all sit in the 2nd row. On longer trips, the 8th seatback stays folded and one of the kids sits in the 3rd row for more room. Having the 8th seat really is quite versatile, and I didn't care about the sunroof anyway.
2017 Pacifica Limited - Molten Silver/Mocha
8 Pax - Vac - SafetyTec - UConnect Theater & Sound
20" Wheels - Tow - KeySense - Splash Guards
2018 Mitsubishi Outlander PHEV GT