At some point when William Gau lived in North Carolina, he came into possession of an early E3 that someone had cut the roof off of. Amazingly, the floorpan was stout enough such that the dumb thing didn't collapse in the middle. This is the car which contributed to the famous LOSER picture from the first EastFest.
This is a photo of my strut brace that I made myself. It made a huge improvement to the front end feel of my Bav. Jim Bartridge has the same one on his 2500. Al Taylor has one on his racing E3. It does fit a stock E3 with original Zenith carbs and original air filter housing. The problem comes with Weber carbs, since most people use the spacer to raise the webers so the linkage works. What this does is raise the air filter housing which now will interfere with the strut brace. One solution is to go with different air filter housings such as the K&N's. I think it should clear a L-jet set up but I have never tried.