Be aware, these 5000 Mhz RAM are, even for a 16 GB kit, extremely expensive.
The Vengeance LPX DDR4 5000 MHZ 18-26-26-46 1.5v 16 GB DDR kit will set you back 1080 dollars. For comparison, the 3200 MHZ version of the same kit costs 85 Dollars.
Corsair mentions that an X570 motherboard is most likely needed to utilizes these RAM at their maximum potential, and yes, Corsair will sell you a Vengeance Airflow Fan to provide additional cooling if you want to overclock, and the pure aluminium heat-spreader isn't enough.
so, if you have too much money, and nothing to spend it on, go ahead and buy a few kits.