Why is my first question?
I can understand upgrading to new pads. But are your rotors warped? Are you moving to drilled/slotted? If your rotors are not warped then just get them turned and your fine. The brake hardware kit can be reused but you will need to do some other things. I don't know your level of mechanical knowledge so I will just cover everything.
You will need parts cleaner, and preferably a bottle of brake cleaner. If your going to reuse the hardware then you will also need a brass wire brush. As you replace each pad you will need to clean the clips back to like new. You will also need to regrease the floating caliper pins. So go ahead and get brake caliper grease too. You will need to inspect all the rubber components, bushings, and protectors to any tears or damage. Be very careful with these they keep brake dust out of caliper pins and keep them from seizing up.
To remove the brake rotors on some cars requires an impact wrench for taking off two screws. Also some rear break calipers need to be rotated as they are pushed back in and require special tools.
Once you have the caliper completely cleaned and greased and the brake clips/shims looking like new you will need to inspect the piston on the caliper. Look for any damage or tears. If it looks great then clean it very gently with a q-tip. Just enough to look decent not perfect. The brake clips do however need to be perfect. Then push the caliper down all the way on the fronts, I dont know about your car but some vehicles require special tools to do the rear brakes. None the less once you have the piston pushed all the way in to the caliper then install the new brake pads. Do the same for the rears but make sure you find out if you need tools to turn the piston as its depressed. If not you will press to no avail.
What needs to be replaced is really up to you doing your checks first. If the rotors are not damaged or warped unless your upgrading have them turned. If the parking brake shoes are not damaged or worn very much leave them alone.
It is good though to every 6 months or every year take your calipers apart and regrease them. This allows you to check for stuck pistons.
Also you will need to bleed the system. Its a great chance to bleed out old fluid and any air thats in the system. If your brakes aren't painted this is your chance with the system taken apart. You can use parts cleaner and about 1 can of brake cleaner per caliper to clean them really really well and paint them.
Make sure no brake fluid or brake cleaner touches the paint on the car!!!
Again I don't know your level of mechanical awareness so if some of this you know im sorry.
