Really can't understand why .Keep yours mint it'll be worth a fortune,I'm happy to say I've taken 2mm off my tyres and I've only done 5 miles this week.if mine ends up in the big scrap heap in the sky before me I'll be happy,,and had my money's worth out of it.never bought it for an investment just the pleasure of driving.but each to their own good luck with the polishingBetter condition of the car means higher value.
Wether you want to sell or not.
The M cars are getting quite rare and should be preserved,