As you get faster you'll find that you are managing the brakes for more of your 20 minute session. If you just beat them to death your track pads will wear out super fast. So if that is acceptable...then OEM brakes will work.
My PF01s on OE brakes lasted 1.875 weekends. When I did track my E90, the pads lasted 3 weekends with about 50% of the pad left. I think most will agree that a set of high temp pads lasting 1.875 weekends is a good sign that your brakes, as an entire system, are inadequate.
So why keep sinking money into a system that isn't up to far for the demands? Just my $.02.
2015 F34 328iX GT Glacier Silver
2011 E90 M3 Monte Carlo Blue
2004 E46 M3 Imola Red