The front of the Bug isn't so bad
Sure you could clean up some things,but the lion's share of drag is due to the roofline.
The Herrod Helper of the 1970s helped a little,providing a little centerline flow reattachment.
Ernie Rogers took it a step further with his 'Bug-Wing' rear spoiler.
Anything to fill in the wake will help.
You can see how Kamm 'fixed' this Adler sedan by lofting the roof up to the streamline pathway
If the roof varies from the streamline pathway any at all,you'll have separation again as in this Citroen
or Z-Car
The doctorate-level aerodynamicists would tell you to attack the back of the Beetle.They've been saying it since 1922.
This VW Student gets to Cd 0.30 in part by keeping to the streamline pathway
For VW's Audi TT,they 'reach up' to the pathway with a spoiler
For a lot more money,VW will push the Audi's roof even higher
For the most amount of money,VW will sell you the 1922 shape!
