Insurance premiums are currently not higher than comparable cars. However, I fear that might change once a number of Model S's are inevitably involved in accidents. This happened here in BC with the Roadster. Once ONE person was hit (no fault!) and their claim went through, the premiums for everyone shot up.
Also, we previously owned another all-aluminum car, an early Audi A8. At the time (late '90's), Audi did specify that structural damage to the body required specialist repair at designated centres in major cities. This may or may not still be the case. If it were me, I would talk to Tesla, and with their help pick a body shop VERY carefully!
Sorry, not the best news, but probably realistic.