They might have looked scruffy (and the 917 was very scruffy indeed!) but the Porsches beat the Ferraris at almost every event they competed in.
IIRC the only 512 victory was posted in the hands of a 'privateer entrant', a certain Roger Penske at the Daytona 24 hour.
Indeed, functional doesn't have to look good! I remember the Can-Am version of the 917 (917-30??) going past me at Mosport, and feeling heart flutter from that monster! Turbo 917 = Yikes!