gambit22

Can someone help me chose what car I should buy. Today I test drove a brand new STi8 with PPP fitted and a used Mercedes CLK 320 Cabriolet on a 99`V plate with 45k on clock. I just cant decide which I should buy. I must take depreciation into account which is likely to have best re-sale value in a year or 2. Also can you tell me if this is good deal, I was offered today a brand new STi8 with PPP thrown in available for delivery now for £25k from a Subaru dealer. I know both cars a very different so I would appreciate any advice to sway me between the two. Thanks