I made 2 minor adjustments to make it fit better though.
1 - I lowered the center panel for less obstruction to the brake lamp and camera.
2 - I added a very thin strip of rubber between the panels to angle the ends for a better look.
** Neither are necessary to use this though. It will fit unmodified. The photos from post #1 are after the adjustments.
First, the pocket for the brake light is a little higher than the actual brake light. Not a huge deal, and it doesn't prevent the light from being visible. The photo here show stock and modified. You can actually lower it even more than I did, but I was trying not to go too far. I lowered it an inch, but you could probably do 1.5 if you wanted to center it in the pocket more.
Although the minimal obstruction isn't an issue with seeing the brake lamp, I noticed that if you use the rear view mirror camera and have it aimed as low as it can go, it will be partially obstructed unless you do my modification. If you aim you mirror camera a little higher you don't have any interference at all.
In this photo, that white line is actually the rack. I assume it looks white because of the sun hitting it and the camera's extremely close view to it. These images were taken with the camera aimed as low as it will go. As you can see, with the 1" adjustment, there is no issue with the camera's view.
The other issue I had was that it wasn't as close to the cab as I liked. This isn't really an issue, but more a matter of preference I guess. What caused this was that the bottom of the pocket that is supposed to go around the brake lamp actually hits the lamp in its stock configuration if you try to push it all the way forward.
By lowering 1" it clears the lamp and can be moved forward so it's nice and close to the cab. You'll notice in the captions I noted the alignment with the bed rails. This is a very minimal difference, and again not an actual issue. Just me being super picky about how it looks.
The adjustment for this was super easy and not even really what I would consider a modification to the rack. I simply added a very thin piece of rubber strip to the back edge of the panels where they bolt together. This creates an angle at the joint instead of a straight line. The wee bit of angle is all that's needed to adjust the alignment with the rails.
You'll notice I also mentioned the interference with the cover. It's minimal, but when folding to the 3rd flip it makes a little contact with the uprights. I didn't like that. Adding these angles completely eliminated that contact. Although other covers (such as a roll up) will likely have no issues at all. The image below is not the best angle of the folded cover, but you can kind of see it in the side view two photos ago. It is worth noting that in order to fold it flat the to the cab (vertical) you need to loosen the two knobs on the MX4 and slide it out a bit. Yes this kind of defeats the purpose/convenience of the MX4 so maybe you'll want to buy a cheaper cover that doesn't do that if you plan to go this route. There's no sense in spending extra for a cover that folds flat to the cab if you can't/won't fold it that far. In this photo, it's as far as I can fold without loosening the knobs to go vertical, although this is full folded (horizontal) and buckled down.
Also a small thing I did since I made it sit so much closer to the cab than I think they had designed it to. I added a strip of rubber to the edges of the rack. The rubber is only about 4" long and applied to the two vertical edges by the brake lamp. That way if there cab/bed should flex and the rack contacts the cab it doesn't scratch my truck. This probably isn't necessary but I had the materials and it took about 3 minutes to add so why not do it.
The last photo shows how I made the modification. It was simply a matter of drilling 8 holes (4 on both end panels). I applied tape to prevent scratches from the chips made while drilling, and to aid in layout of the holes. As noted at the top, I did 1" but you could probably do 1.5" if you want to. I originally considered this but wasn't sure if it going so low would interfere with my cover. Now that it's done, I don't think it would have, so you have options.
And for any of you who are concerned with drilling holes. Don't be. The rack is made of Aluminum, so it won't rust. That's one of the reasons I bought this particular rack. I wanted aluminum so it won't get rusted and ugly after a it's been on the truck a while, and it's lighter than a metal rack.
TL/DR:
Aries Switchback fits 5th gen 1500, and can be used with a tonneau. It fits without any modification, but lowering the center panel allows a clear view to brake lamp and mirror camera.
