This is a huge mistake
1. The body kit you buy will not fit the car nearly as well as the factory parts did.
2. You will severey devalue the car by putting a body kit on it.
3. Bodykits are usually made out of low grade fiberglass that will break easily and has a lot of pinholes in it or urethane which is very difficult for paint to adhere to.
4. An avalon with a body kit would look stupid.
5. It will cost thousands of dollars to have the body kit installed and painted correctly by a professional and it still will not fit properly