1) My car has a scratch on the panel under the rear door, which is about 10cm*2cm large and has been to corrosion because not repaired by the former owner. I thought it is nothing before but when I sent my car to the dealer for repair estimation, the quotation is surprisingly high as 820$(tax incl.). And they cannot guarantee the reoccurence of the rust because the area has been already rusted. I'm hesitating about the repair because of the high cost. If I leave it alone, is there any serious effect?

2) What are the summer service and winter service? Do they mean that while I follow the service steps described in the user's guide, I should do the above two maintainance additionally?

Thank you very much!