Narrow Car Seat

Does anyone drive a Ford Explorer (2016) and have 3 car seats? I will have my oldest in the Graco 4 ever in the back row. The middle row will have my baby in the rear facing Graco snug ride. I plan to buy a new seat for my middle. He's currently in the Evenflo Maestro. I'm having trouble finding anything that's any narrower and not super pricey. Thanks!