Best residuals

[sparky32]

Hi, tormenting myself with buying a car, shortlisted AMG C63 (2014), Jag XFR (2014) , Porsche 911 Gen2 (2009/10) as within budget and possibly a Mustang GT if I like the drive, bit of a random mix I know but anyone know what would have the best residual over the next 2 years as this is a key factor, would it be the 911 as they must be starting to flatten out now? Worried the C63 will plummet what with the new version etc.