They took the standard Aventador, chopped off the roof, gave it new bumpers, a great looking paint job, some modifications to aerodynamics, and created this mind blowing design. Its the one-off(read- super exclusive) Lambo Aventador J. It was so stunning, all the eyeballs were glued at it at the Geneva Motor show. It has been aptly named to refer to FIA's 'Appendix J' which defines race car design.
They literally chop the roof actually. Hell they wouldn't even think of on a car, err, spaceship like this one. The roof acts as a very important support for the car's body shell. There are intricately designed support bars behind the seats to give extra support. Because of the missing roof and the smart use of lighter materials and redesigned components, there has been a lot of weight saving done.
Its now lighter than the standard aventador. Hence, acceleration should be blazing fast and in fact its should be quicker than the standard aventador to 62mph, which does it in 2.9 seconds flat. Check it out and you gotta be mad to not want one.