Drilled discs are all well and good in cooling terms, but only if the rest of your braking system is up to scratch too. I'd be looking at the state of the existing pads, discs and fluid first.
If your fluid hasn't been changed in the last couple of years, do that before going anywhere near the discs and pads.
If the pads and discs are getting low in terms of thickness, and near the end of their life, then that won't be helping matters.