that's a call you will have to make,
what did insurance settle with you for?
Take your money pulled out from insurance, less the 2K buy-back option, less the costs to repair and inspect the vehicle and see if it's worth while, also, considering how much you got from the insurance, could you buy another M3 just as good as yours?
As far as selling the wreck, talk to the sponsors on here, maybe one of them would be interested???
1992 325i / Briliant rot - SOLD @ 301,000km
1998 318is / Arktic silber - SOLD @ 207,000km
2007 335i / Jet Black - CURRENT @ 28,000 km