chip with 4.10s?

When they say reflash, you are flashing or rewriting the original factory chip using an aftermarket flasher such as Hypertech, or the Diablo Preditor. This limits some of the changes that you can make. If you go with a custom chip you actually remove the factory chip and replace it with the custom chip. With a custom chip you can make more changes such as A/F ratio's, as well as, the typical speedo, shift points and shift firmness.