MELBOURNE, Australia — General Motors' Australian unit, GM Holden, says it is offering the most fuel-efficient midsize SUV in the new rear-wheel-drive version of the turbodiesel-powered Captiva.Powered by the 2.0-liter turbodiesel engine from the Captiva all-wheel drive (AWD) lineup, the manual-transmission 2WD model will lead its segment with fuel efficiency of 32.6 mpg, while the automatic version returns a still impressive 27.7 mpg, says GM Holden.The automaker's marketing director, Philip Brook, said the two new variants are meant to give SUV 'flexibility and turbodiesel power plus the fuel efficiency of a much smaller vehicle' for customers who can live without all-wheel drive.The new five-seat 2WD Captiva still offers traction control, active rollover protection, electronic stability control and four airbags, all as standard equipment. The 2WD Captivas start at the equivalent of U.S. $29,265 for the five-speed manual transmission version and $30,988 for the five-speed automatic transmission, which is some $1,725 less than their AWD equivalents.What this means to you: Every segment everywhere is looking at fuel economy these days. — Laura Sky Brown, Correspondent