Honestly, I've been racing on the stock setup for years. It really hasn't been an issue.
In fact, I found some of the racing pads are a bit too hard (at least for vintage racing, where we have fairly moderate engines and tire sizes).
So I just run whatever "street/performance" pad I can find (like the upgraded street pads from Moss). I've always run stock rear linings too.
I usually get 3 or 4 weekends out of the pads and at least a season (8 or 9 events) out of the stock rotors.