Overall, this seems like a nice box had to do many modifications on the vehicle and the box itself, for it to fit barely .cut out for the seat belt needs to be a little deeper so the box sits more flush on the driver side rear wall. Also, maybe a little less bedliner in that area would help had to notch the front of the box that was hitting the back of the seat caused a bolt to poke through the carpet on the back of the seat in two places not good on a brand new truck had a cut two threaded studs off in the middle, cut the plastic interior panel and remove and reroute wires in the middle of the seat also, you will never get speaker rings or grills on your speakers. It won't fit had to install subs only. after a bunch of extra work, finally was able to get it in and the seat barely closes. I think the makers should pay attention to a little bit more on measuring or make the bottom of the box a half an inch skinnier the piece that says fox box any way if you buy it plan on extra work not a plug and play thing not absolutely thrilled, but it does seem to be like a decent box and there's not much out there right now
I apologize for the fitment issues that you had while installing your sub box. You are correct about the top portion of the box. We were getting mixed feedback with some customers saying it dropped in and others saying they had to push very hard to get the seat back to latch. We were just informed by an employee at the plant where they are made in Texas, that depending on the interior fabric options, the thickness of the rear seat varies. Evidently the truck we designed from had the thinner rear seat. The difference is only a 1/4 inch so we modified the design and all boxes going forward are 3/8 inch thinner at the top to work with all seats that may come in Tundras.