Not really, not if you're going for a sealed unit. All that you need to bear in mind if you're going with the Arc Mini is that the rear fan is a 120mm. The top fan slots support 120mm and 140mm so even the H100 should fit. In fact, here is an example that I found Nope. ATX power supplies work in mATX cases. Some mATX cases can't take some of the longer power supplies (like a 1200W) but the Arc Mini doesn't have that restriction and you're not really likely to have a 1200W power supply any time soon.