Complex sentence: A variant of the car, dubbed MP4/7B, featuring an experimental active suspension system, was introduced in testing for that year's Portuguese Grand Prix, though it proved insufficiently reliable and was not used for the remainder of the 1992 season.
Split into simpler sentences: A variant of the car, dubbed MP4/7B, featuring an experimental active suspension system, was introduced in testing for that year's Portuguese Grand Prix. It proved insufficiently reliable, and was not used for the remainder of the 1992 season.