There’s an all-new Audi A3 for 2013. It’s slightly bigger, yet lighter, has three new engines including a more powerful diesel and is offered with an expanded line of body styles: two- and four-door ...

Part of the hesitancy, most insiders believe, stems from a general lack of understanding among consumers here about the benefits of modern clean diesel versus the old (read: loud and dirty) variety.

The wheelbase of the 2013 A3 increases less than an inch from 101.5 to 102.4, while overall length remains unchanged on the three-door model (which isn't expected for the U.S.) at 166.9 inches. The ...