This C63 507 craps on the M3 in terms of looks and engine sounds alone. Now it is just a couple of HP shy of a BLACK SERIES - using the same part# lightweight internals - and even has the option of some decent race metrics on the idrive. In terms of handling if you replace the skinny 255's with some wider Michelin PSS the coupe will keep up with a M3 with light power mods around a track.
What's more there is rumour that is 507 series will simply replace the P31 package in terms of price - it's what Benz do - option the heck out of the outgoing model so they eat some of the depreciation for you.
This is a proper and deserving finish to a mighty fine German muscle car.