if you dont buy an M, you will alway wish you had whenever you see when fly by you on the highway. If you can afford it, go for it! You only live once. You should consider taking the 0% financing and make sure you research the price you should pay by checking out the dealer invoice on the internet and then negotiate, negotiate, negotiate.
And another good reason to own an M---you get to join the "Chrysler 300M Enthusiasts Club" and meet some realy great people! http://www.300mclub.org/