MPG-o-Matic 2010 Mercedes-Benz GL350 BlueTEC Review Summary: The 2010 Mercedes-Benz GL350 BlueTEC is one of the most fuel-efficient seven-passenger luxury SUVs on the road today. From the calm and comfort within the GL350’s well-crafted cabin, one can only wonder why so many manufacturers have been slow to embrace clean diesel as the ideal solution for premium vehicles.