Thats just sickening... I am amazed they left the tires alone, seems like tire slashings are out of style...
Too bad the car is not a total loss, I'd hate to have to drive it after something like that happened. New windows, expensive paint removal for the interior if not new seats/upholstry, and a whole lot of paint work. It can't cost more than 10-15k if he gets it done by the pros, so no it's not a write off. Although I am willing to bet the M3 owner has cash to burn and he is likely going to pocket the insurance money, fix the car as cheaply as possible and sell it off to someone else. I still can't think of any possible reason why infidelity would lead to 10k in vandalism damage.