Hmmm....u seems very interested in the M5....
i think M5 is more suitable for ppl in the age of 35 n
above...
jus my personal point of view...
if ur dad dun mind n since u like it den go for it loh...
no doubt this is the best performance M5 BMW ever built...
it shd be out in sg by june.... 
My other options for u would be...
European car:Mercedes E55 AMG,Masseratti Quattroporte,Audi S8,is it
possible
to get a Bentley Arnage or Rolls Royce Phantom???
Japanese car:can only think of Lexus ES430(the closest price
range)... 