I'm very wary of the Mendeola rear suspension design. The system uses design elements like highly stressed fasteners in single shear, loads applied to the middle of tubes, and pre-buckled tubing. Any design book, whether an engineering text or those for us 'layman', will caution against these errors. Carroll Smith (Engineer to win) goes much further then caution!
I asked Mendeola about the issues I saw and was basically given an answer that "the vehicle will never create loads large enough for it to be a problem". Which, considering some of the track monsters here, I'm not very confident of. I would think that if you were to completely redesign the rear suspension of a vehicle, you would do so without including what have been accepted as "major engineering 'errors'". The system may very well be overbuilt for a Volkswagen, maybe even a track-day GL monster, but if I can see errors in the basic design I lose all confidence in it's claims.
It should be said, however, that the front system from Mendeola (for the standard beetles) has no major visible issues. My only complaint (from a purely performance perspective) is the choice of ball joints over rose ends. But that is an acceptable downgrade.
-Dave