08 Sienna has throwaway rotors. Don't bother turning them or you will end up with warped rotors in short order. You can pick up good quality rotors for about 50 bucks a piece and good pads for about 50 bucks. If you are reasonable handy and have the tools replacing front pads and rotors on a Sienna should take you less than 90 minutes, even if you are meticulous about cleaning and lubing (as I am). Parts should be about $150 plus brake cleaner and silicone lube. One other trick I use on my Toyotas is to put some "Disc Brake Quiet" on the back of the pads, even if they have shims. It is goopy, rubbery stuff that keeps your pads from squealing. It peels off like dried caulk at the next brake job and I NEVER have noisy brakes.