The inline 6 has been replaced by the V6 engine because of its compact size and high
performance engine is why it's the best choice if you're looking for a high power engine while still maintaining a great fuel economy for your SUV. The 4 cylinder as a straight or inline is standard in most vehicles and is considered an economy engine. Its lower emissions and fuel efficiency makes it the engine of choice for those concerned about the impact on the environment. So to determine which engine is better will depend on what you are looking for in the next automobile you purchase though more cylinders equal more power when comparing different engines.