Ok, so, warranty costs (as per BMW insured warranty website) - this won't take into account any renewal discounts, which I think are around 15/20% but that's not clear - perhaps they are now more generous based on mattyg's quote?
So a new policy -
2020 840d xDrive Coupe - Comprehensive, £100 Excess, Roadside Assistance, 25k miles -
£2825.00 per year.
2020 M8 Competition Coupe - Comprehensive, £100 Excess, Roadside Assistance, 25k miles -
£2825.00 per year.
2020 M2 Comp - Comprehensive, £100 Excess, Roadside Assistance, 25k miles -
£2121.00 per year.
2020 M5 Comp - Comprehensive, £100 Excess, Roadside Assistance, 25k miles -
£2121.00 per year.
So based on this limited research, it looks like M cars do have a flat rate, unless it's an 8 Series, then you get ripped off even more.
They do seem to have changed the costs recently as well.
Never seen that. That would have made an M8 Competition cheaper than an 840 diesel?