depending on what you buy auction houses provide finance and warranty
all C63's are AMG, just depends on whether you go for a 507, black etc..
yen coupes as well as sedans will go for around the 100k mark. with little to no KM's either. and if its less than 3 years old, chances are the new warranty is still on it..
i'll have a look tomorrow at price vs year/kms they have been selling for and pm you