I ordered a new topper for my 2018 GMC 2500. I went with the ARE V-series so I could get the sliding side windows and ordered a front sliding window to get the best possible ventilation. We camp a handful of times a year and I pull a travel trailer with the truck. We also have 3 small kids in the rear seat of the crew cab. We are looking at getting a Lab puppy. My plan was to transport the dog in a crate in the truck bed under the topper, no room in the truck. I have thought extensively about heat issues back there if it's really hot out. One thing I've been thinking about lately is the fact that I replaced the muffler on the truck, 6.0L with a big Magnaflow 12909. The truck is not loud at all in the cab, obviously a little louder under load, but do I need to be concerned about it being too loud in the truck bed under the topper? Exhaust exits in stock location out of the rear corner and truck has a bed liner if that matters. I think it will be fine but let me know what you think.