I think if you bought a brand new C63 you'd take an absolute bath on it over two years, unless you figuratively raped the sales person.
Why tie up a huge (comparatively speaking) chunk of capital in a deposit and spend two years wondering whether you're 'in funds' or not?
If the downside to leasing is a lack of flexibility then the upside is absolute cost transparency; you know that the car will cost you (servicing aside) 3+23@ £527.00 no more, no less.
Let MB Corporate or Lex or whoever is funding the car have the sleepless nights over whether they've calculated the RV correctly or not.
Let me (prematurely) welcome you to the C63 club. Make friends with a tyre fitter and petrol pump attendant.
Gone but not forgotten:
325i M Sport (E92), Black Sapphire, Coral Red Dakota, 19" 225's, Seat Heating, 6FL and de-badge
Replaced by 6.2 litres of AMG powered C class.