MacworldiFixit has posted its video teardown of the new M4 Mac mini, and as usual, its a fascinating study of how design, engineering, and technology come togetheror in this case, taken apartWhile a lot of people are interested in the inner workings of Apples products, the Mac mini might draw more interest than any other product. Theres a widespread belief that users should be able to perform a certain amount of customization and upgrades with desktop computers, even with Macs. And the Mac mini has been used in unique situations and projects. Teardowns like iFixits dont just satisfy curiosity, they provide useful information.Watch iFixits video, and after that, here are a few takeaways from the teardown.Its packed to the gillsThe M1 and M2 Mac minis used an old design and left a lot of space inside. With the new design, the Mac mini is immensely packed. Its an incredible feat of design and engineering, but it also provides a serious hurdle to do-it-yourselfers. Which leads us toIts user upgradeablebut is it, really?Apple clearly has an idea of what components should be accessible, and its obvious in the Mac mini. For example, the CMOS battery is designed for access without diving deeper into the machine. In fact, its the only component thats readily accessible.We heard early reports about the Mac minis SSD being upgradeable and the iFixit video provides more info. The M4 and M4 Pro Mac minis use modules of different sizes and iFixit couldnt get its Mac mini to work when they tried swapping the SSDs.iFixit often refers to the Mac mini as being upgradeable, but being upgradeable involves the ability to remove a part and replace it with an available part. At this point, theres no available part for the Mac mini. Apple uses a proprietary SSD module that is nothing like the NVMe SSDs used in Windows PCs and is made by third parties such as Crucial. You cant buy a NVMe and pop it into the Mac mini.Could a company make a Mac mini-compatible SSD module? Maybe, but would it be worth the investment for them? Its hard to say. The Mac minis SSD is similar to that of the Mac Studio, and a Kickstarter project to make a third-party Mac Studio SSD upgrade has exceeded its funding goal, but it has only 142 backers. Granted, the Mac Studio is more of a niche than the Mac mini, but it still seems like a low-volume endeavor.In case youre wondering, the RAM is incorporated in the M4 chip, as it has since the M1. There is no way to upgrade RAM after purchase.The fan is bigThe ring of vents at the bottom of the Mac mini leads to a fan that takes up a considerable amount of space (and even more space in the M4 Pro model). I cant help but wonder if smaller cooling units can be used, which could make the Mac mini even more tiny.For example, Frore System makes solid-state active cooling chips that are super thin and effective. Last year, I covered how they modified a MacBook Air with its cooling chips, which allowed it to stop throttling to maintain a proper operating temperature. I dont know what a system like Frores would cost to implement, but I imagine its not as cheap as a fan, so it may be too pricey for consideration.