Upgrading pads and fluid is a good idea. Street pads will not last under race conditions. Street fluid can be dangerous. You don't need to replace everything though, stock calipers/rotors with better pads will work great to get you going. Then when you've used up the first set of pads you can decide if you want to look for a larger rotor and caliper setup. Do check all your lines and make sure they are in good condition. Old rubber lines should be replaced if they look remotely suspect.
For fluid look at ATE Type200 as a great affordable option.
For pads, the raysbestos ST-43 is the easy button for great endurance pads. They aren't really cheap, but they last a long time. It's not unheard of to get more than 5 races from a set. We've gotten almost 10 out of rears at 5+ from fronts. There are other options that people swear by, but I'll never use another pad after the success we've had with ST pads.
For rotors, you don't need anything special, just plain new rotors are great. Cross drilling/slots won't really help you much and can lead to more failures than advantages. We've always used basic OEM equivalent replacements from rockauto.
Edit: You can roll the dice with the existing street pads for a race and see how far they get you before vanishing, but it's not a bad idea to have a spare set in case they are some autozone special.
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