Its all well and good saying bank it but one claim could pay for the whole thing.
When I had the warranty on my Z4M coupe the xenon bulb and ignitor went that one item was more than the warranty for the year.
The 35s have complicated engines and electronics there is plenty that can go wrong, tbh the less you use the the more likely it will have issues like injectors. They have to be replaced in 3s, just replacing the injectors the 'Cheapest' i found from a specialist was £1350, then theres the water pump, roof, wheels, adaptive springs etc etc The adaptive sus is £400 a corner, they do leak its a matter of when.
Nothing may go wrong but generally when something goes wrong a few things go too. Its usually not the parts its the labour.
The injectors fro example if they go and are left can cause all sorts of damage like bent rods etc tracing it all back takes time and costs labour.
2 of one 2 of another.
Depends on your experience the people who've been lucky will say don't bother, the ones that have had lots of work will tell you the opposite. Any car can turn into a money pit.
Depends on the car and how long you've owned it. If I had owned from new or nearly new i probably would be less inclined as I know how its been treated and looked after etc
BMW is the best bet IMO nice and easy no worries with filling claims just take it to any garage and they will fix it regardless of labour.