Hyundai made some news last fall when it launched the all-new 2011 Sonata with a four-cylinder-only engine lineup. It now looks like General Motors might be following suit for its mid-sizers. By leaving out larger V6 engines as a possibility, Hyundai was able to design a lighter structure while still meeting new safety requirements and maintaining passenger volume. GM has already opted for four-cylinder engines in the new Buick Regal even though it didn't get any structural weight advantage since the Opel Insignia that it's derived from is available with V6 engines.
The 2012 Chevrolet Malibu is also expected to eschew V6 engines when it debuts next year and both it and the Regal are likely to benefit from GM's next-generation mild hybrid system. GM is moving toward down-sized engines across the board with direct-injection and turbocharging for its next generation of vehicles as it strives to meet new fuel economy standards. Given the relatively small percentage of mid-sized cars that are actually purchased with the more powerful V6 engines, it makes much more sense for automakers to design vehicles around the smaller engines and then use turbocharging and hybridization to provide improved performance for the few customers who want it.
[Source: GM Inside News]