I haven't seen very many full custom water cooling setups in the Tower 300 yet. It is a tight fit depending on what components you have to work with for sure. It took me a few days of planning and a couple days to really get it built like this looking super clean. But end results speak for themselves. I migrated most of my existing waterloop with the addition of a smaller reservoir to this case. It all fits.. barely! I was going go go hard tubing but after a little trial and error decided against for ease of maintenance in such a tight space. If you take your time, soft tubing can looks great and SO much easier to deal with. The case itself isn't exactly what I would consider Micro-ATX size as it's quite tall and still has a decently large footprint. But you definitely save desk space in depth. Love the vertical GPU look and the Pump/Res being the centerpiece.There were 2 mods I had to do to get the airflow optimized and 1 to get the my GPU to fit and still use the included cable cover at the bottom. Mod #1&2, Get better airflow. The platform in the center where the Pump/Reservoir are mounted to is directly above the power supply. With the power supply mounted fan down (as it should be in this case), there is about 25mm of empty space between it, and the bottom of that center platform. Now, you can mount a fan on the top side of that platform if you wish. I personally don't want the ugly backside of my fan showing so I wanted to find a way to mount it up under that platform as an intake fan. Issue is, the standard 120mm-140mm fan thickness is exactly 25mm. So not enough space. Even if you could squeeze one in there, the airflow would be completely choked off being so close to the PSU. What I ended up doing was ordering a slim 15mm thick Arctic brand 120mm PWM fan. It fits under there perfectly with roughly 10mm to spare. They make an all black one and the cables are also black. So it just hides under there completely out of view. It runs very quiet and moves a surprisingly high volume of air! Just that mod alone dropped my case temp by 8c running at around 60%. Second mod, not really a mod, is to now reverse the fan/fans on the back of the case to be intake instead of exhaust. This brings in cool air and blows it across the back of the motherboard and around the sides feeding my 360mm radiator even more cool air. So I have cool air coming in from the bottom and back and heat being exhausted out the right side and top. I did a couple different fan configs and this one drops the temps the most. Mod #3. Fitting the clip in cable cover under the GPU. Out of the box, you have exactly 280mm of GPU space to work with if you intend on using this bottom cover. Any longer and you can simply pull it out and fit longer GPU's. My GPU waterblock is roughly 290mm. What I did was dremel out a rectangular cutout in the center of that cover to allow the longest part of my GPU to pass through it. Fairly easy mod if you of course have the tools. Without that cover it just didn't look right with all of my PSU and cable extensions exposed. I wanted a no compromises, clean build so I did the extra work.NOTE: I am using an EK P360 Radiator which is exactly 39mm thick. Most AIO radiators are about 10mm thinner and have plenty leave plenty of space. With the addition of standard 25mm thick fans, my setup JUST BARLY FITS! No cutting of that center platform needed. There is quite literally 1mm of space left so the fans do not rub. I took a bunch of pics so take a look and hope this info helps!!I absolutely loved building in this case. Fairly easy to cable manage in and very little wasted space. Its a head turner for sure.