You can always opt out from their recommended repair center and go to the one of your choice. If the cost run over, they will directly work with insurance to approve additional cost. But I am not sure about parts, I think they will ask to use after market parts if vehicle is certain years old, i am not sure if you can opt out from aftermarket and request to use new one or not, but you can always ask them. Lot of times it depends on insurance company , these smaller cheap insurance companies are pain in as*, to deal with.