The importance of genuine replacement parts:
Don't be fooled by "lifetime warranties" on imitation parts. Significant additional costs can be incurred if these warranties do not include labor.
If the insurance company insists on imitation parts, ask for proof that they are equal to genuine parts in terms of fit, finish and corrosion protection. In making your final decision of which parts to use, consider the hidden cost of future repairs, reduced resale value, and the possible risk to passenger safety which you may have to face one day.