[FISH11]

If you don't get the transducer with 83/200 kHz and the 455/800 it won't have the benefit of being able to get regular sonar on 83/200 or 50/200 kHz and the dsi (down scaning sonar) on the 455/800 kHz. The benefit of the HDI unit is it can display both if you use the correct transducer. The non-HDI unit either have regular sonar or DSI not both. The Elite 4, means it also has GPS the Elite 4X does not have GPS. It is not worth buying the HDI and getting the 200 kHz or 83/200 or 50/200 kHz transducer only because it will cost a lot more later to purchase the multiple frequency transducer by it self, to make the system do what it is capable off. Get the unit packaged with the 83/200 and 455/800 transducer.