Complex sentence: In 1995, Alpina introduced an electrically heated catalyst, which they called "E-KAT", in their B12 5,7 E-KAT sedan based on the BMW 750i.
Split into simpler sentences: In 1995, Alpina introduced an electrically heated catalyst. Called "E-KAT," it was used in Alpina's B12 5,7 E-KAT based on the BMW 750i.