My car (2012 Mercedes-Benz E250 CDI - 4000 miles on clock) was swamped whilst travelling on a flooded road. My car insurers have agreed to pay for a new engine. The Mercedes authorised repair garage wants to replace, as a matter of course, the catalytic converter, the intercooler and the turbo unit. The engineer appointed by the insurers says replacements are not necessary. Should I insist that these are automatically replaced, particularly the catalytic converter as a significant amount of water poured from the exhaust when the car was winched onto the breakdown truck. I am concerned about subsequent warranty claims for these items being refused.