The 9 is a generation 2 networkable and only has down imaging in mega. The 8 is a gen 3 mega side imaging + This will be the better of the two if you are wanting mega side imaging as well as mega down imaging. They should come with everything you need transducer and cable wise. Gen 2 did have mega, as it is what I have. Gen 3 was mega imaging + and they came out with the 7s and 8s in mega during that gen