Complex sentence: A performance oriented sedan of a similar size to the Corona, based on the Toyota Celica platform, was introduced in 1970, called the Toyota Carina, and available at a different dealership sales channel called "Toyota Store".
Split into simpler sentences: A performance oriented in-house competitor called the Toyota Carina, close in size to the Corona and based on the Toyota Celica platform, was introduced in 1970. It was available at a different dealership sales channel called "Toyota Store".