Most $100-$150 mothrerboards will last 3-5 years and then it is time to upgrade anyway, really no point in spending $350 except for bragging rights.
The Switch 810 is a good case if you want a "cheap" case made with a lot of water cooling options, however it is full of plastic and not something I would ever get.
You can get a high quality gold rated modular PSU for $50 less, only reason to get an AX is if you want to use the sleeved kits which are available instead of extensions.
A good setup of custom made water cooling would destroy any other cooling if you build it accordingly, you can make a dead silent rig with 3-way SLI if you have enough radiator area and quiet fans, you can also make a 3-way SLI rig where neither CPU or GPU will pass 55c at full load.
You don't have to clean it 5-6 times a year if you do it properly from the start, once a year is plenty if you don't put any stupid colors or such in the water.
I just find it very odd that you are willing to spend $200 extra on a motherboard that gives no performance gain at all and not $200 for better cooling.