I am looking for a car to keep long term which may not get used everyday but fun to drive on the odd track day, I was thinking of an M3 4-5 years old with low mileage but I have just seen a C63 AMG on a 12 plate for around the same money as an older M3, I like the interior of the Merc more than the BMW but I think the Merc may be a bit tail happy, anybody got experience of both?