I'm not sure why U.S. ratings are so much lower. It could be the highway speeds we travel at, required crash tests, average temperatures, or it could just be politics used to sell larger pickup trucks. Anyway, we don't have the diesel yet in the US. I'm patiently waiting. However I'm a bit unimpressed with what Mazda has to offer when it comes to manual transmissions. We can only order the 2.0L motor front wheel drive in the base trim package. I'd really like AWD, 2.5L, and stick shift with leather. I'll wait a little longer and maybe send them a letter and tell them to get their act together.