Bit of both me thinks, csi bottom & m3 top x 2.

Have a look on here near the bottom :

http://e31.net/navmodelle_e.html

The engine picy is

Also got a picture of it (the macca engine) out of the car but cant find it right now, that does look sexy (and like 2 m units).

Hope it doesnt suffer from the same vanos issues