I wonder what engine was in the display aircraft, it certainly didn't look short of climb performance.
According to their own website a Rotax 912(S). They have a page that details the conversion here:
http://www.hangardelcielo.com/sistemasfotos.htm
Google translation of the conversion:
From 1996 to date we have developed and tested the systems needed to make our aircraft powered by Rotax 912 and 912S inverted flight and allow all kinds of acrobatic maneuvers without alterations in the supply of fuel and lubricating oil. In the same way the system was developed to apply to the exhaust fumes from the engine.
They even quote a price. Some of the photos and videos look very good indeed. Like this one here:
It looks like the airframes have had quite a hard life performing in many airshows. They do not hold back.
