Since my pony doesn't come equipped with brembo brakes and my rims don't support them. Is it worth getting better pads and slotted/drilled rotors?

 

The general concensus among brake part manufacturers is that blank rotors generally offer the best performance for most uses. Slotted rotors seem to offer some benefits, but drilled rotors don't. They often break/crack easily. Good "drilled" rotors are actually cast that way.

 

At the very least, change the brake pads. Pads from Hawk or even Auto Zone Gold CMax will give you better stopping power and they are much cleaner than the factory pads.