I highly recommend these sites.
The California Look, Classic Volkswagen Beetle, Street and Drag | Cal-Look.com. This is where the biggest names in VW racing and engine building hang out.
Volksrods
Home This is where you will find the most info on body modifications.
TheSamba.com :: Volkswagen Classifieds, photos, shows, forums, and information This site has the biggest parts swap and I’ve always had good experiences. Don’t trust eBay for old used parts; I have been disappointed more often than not.
Now on to the good stuff starting with what you should see first. A 50+MPG Beetle running on two cylinders!
He has the best engine for hyper milling and a lighter car than yours but I think you can still get there. Volkswagen Greats is the best ACVW magazine that ever existed. I have a copy of this issue and several others with similar cars. One day I will dig them out and make some high quality scans for the forum.
I would suggest lowering the car in addition to or rather than use such a tall faring. I can help you with FREE suspension modifications that will lower the front 3-4in. and rear 1-2in. The front rake generates downforce and lower CoG makes a dramatic improvement to stability at interstate speeds. I don’t know what the change in Cd is but I won’t drive a Beetle that is not set up this way.
Any thing more will require a different method or become counter productive using the same. It will also involve fabrication and/or purchase of parts. The low car in the pp video has severe negative camber and toe-in in the rear but it was done that way because they think it is cool. Doing so increases rolling resistance and eats up tires quickly.