DON'T waste your time with a non-aviation GPS in an aircraft. It's the airspace information that you need. Without the airspace and detailed information you are wasting money by estimating distances and not following the direct route. You could say that the GPS will pay for itself in aircraft hire time and may one day save your life or someone elses by helping you to give an accurate radio call and distance calculations. How many times have you heard someone call 5 miles inbound and they are nowhere to be seen for the next 10 minutes?
The 296 craps on Lowrance, especially after the recent *massive* price drop that the Garmin "had to have."
Remember that the 296 is not certified but it contains the identical terrain database to that of the 400 series Garmins etc that you'll pay thousands for!
You can land a 296 for about AUD$1,500 at the moment from the US and about $2,900 for the 496.
Whilst on the topic of importing electronics, most of the big sellers such as Spruce and Gulf coast are offering trendy Vertex Radios (transceiver) for US$179 at the moment so about $250 delivered with the strong aussie dollar. I've bought around half a dozen for flying buddies and my local flying school and they are excellent value, waterproof, robust and very loud - highly recommended for a backup!
PS
That being said, do take a look at the latest Avmap. They have a very large screen and are quite a thin little unit.