CSL V10 is nice.
HAve seen how BMW mechs work on E60 V10's though. Think monkey stuff.
You won't be able to access 40% of the vital parts of that engine in an E46 shell.
Still, great fun!
Funny that the site shows they have flogged the original CSL stuff in a compact
Whilst we are on the engine swap topic:
S62 in E36 sedan
M70 in Compact ( Hartge H50)
M57nII in E30 ph 1
S14 in 2002
S85 in X5