They look like the same design.

 

It is more than just that, the side blinker looks like a VW, the side profile looks like a VW (esp. on the sedans). They look very much like a european car (VW mainly). They also drive like one. That is why I love them [Mazda 3's] so much.

 

There is a reason the Volvo S40 is built off of the same chassis...probably why the 3 has a european apeal.