Toyota new car rust proofing - worth it (Ottawa)?

[pest bye]

I'm planning to buy a new Sienna in the Ottawa area, but the rust proof options is so expensive.Is it worth it to do at Toyota because the quality of rust is better than doing it outside? Or Toyota actually contract out to a rust proof dealer in Ottawa? It cannot be manufacturer rust proof because the car is already out in the dealers around Canada.Any recommendations on a good quality and cheaper place to do rust proofing?Thanks!