Original sentence: Exceptions to the shift to V6 engines include BMW, which specializes in high-performance straight-6s in its sports/luxury cars, and Volvo, which designed a very compact straight-6 engine/transmission package to fit transversely in its larger cars.In 2002, after two decades without a straight-6 engine, General Motors introduced the Vortec 4200 as part of the modular straight-4, straight-5 and straight-6 GM Atlas engine line
Edited sentence: Conspicuous exceptions to the rule are BMW, which specializes in high-performance straight-6s in its sports/luxury cars, and Volvo, which designed a very compact straight-6 engine/transmission package to fit transversely in its larger cars.In 2002, after two decades without a straight-6 engine, General Motors introduced the Vortec 4200 as a standard engine for the Oldsmobile Bravada, GMC Envoy and Chevrolet Trailblazer, as part of the modular straight-4, straight-5 and straight-6 GM Atlas engine line.This has made them popular in European high-end sports-luxury cars where quiet high-speed performance is important