Gutted for you mate.
Happened to a mate of mine recently. Forced the front door when they were out and took his missus brand new 3 Series BMW. Which they never saw again.
He had a lot of trouble with the insurance, as they intially tried to say it was their fault for leaving the keys in the kitchen and not having them somewhere secure. In your own house FFS !!!!!
Al lot of the time it's kids just out to nick a car and razz it around, before ditching it once the juice runs out.
If it's a high end sporty job, it may have been nicked to order and be given a new ID and then sold on.
A lot now depends on who you are insured with and how they deal with it.
Jeez man what do they consider a secure place? That's the trouble now, had car insurance for 20 years and never made a claim, they will try anything to get out of paying up I'm sure