I'll go back and verify what Polaris says. I don't believe they state 30% increase in "efficiency". They claim a 30% increase in "range". That increase might come in the form of increased fuel capacity, increased efficiency, or a combination of both. I'm thinking it's a combination since they are using the word "range". Need to verify their marketing claims though......If it was purely an increase in efficiency, I'd think they would be running all over town talking about this great efficiency advancement. A real 30% increase in efficiency is tremendous. Can't imagine that's true...Maybe though, would be nice. They've got this new Bosh fuel injection system.Most people get around 100 to 120 miles on a full tank riding in the hard pack. The 2011 Rzrs are supposed to be like 30% better MPG so you should be seeing 140 to 150 miles. Sand robs a lot of mpg so expect to fill up alot more.