Unless you have some mechanical/electrical skills relative to german equipment (which I don't see), it WILL be a nightmare. And this is not limited to PK. There are exceptions to this (W124/W140), but even those require you to be on a 9-5 roll when things take a turn for the worst. E60/65s were a nightmare for the dealerships. That, too, a diesel E60 - Hose your money off with gas and stick a light to it.
Now as I'm fresh out of teenage recently, I can see the desire although I never felt one - They don't fit anywhere, you won't be a tuner, and it would never be a build. Trust me, it looks pretentious and stupid to me unless it is an iconic sedan (123/124/126/140). But then again, some people go for the badge.
Till this date, I would still pick a Type-S CL Accord over a C63. They are not comparable, but the C63 just doesn't 'represent'. If you get what I'm saying.
