That is very large, and I think it is too wide and too tall, but it also depends on how you are going to fit it. You won't be able to attach it to the seat itself, due to the shape of the floor. If it isn't too wide for the shape of the floor, you may be able to secure it to the floor under the seat, and have it it stick out towards the rear deck wall. (I would never attach an electronic component to the floor, but that's me.) What I would recommend is that you take the dimensions and make a mock-up out of cardboard...
Best regards,