Personally, I have 2 HB 800 series. One is HD the other is SD. I put the HD on the transom so I could use the HD for side imaging. The SD is on the bow, since SI is limited in its usefulness on the bow, IMO. I use the DI and 2D and mapping mostly on the bow. I have a Lowrance HDI 5 that has DI in it and I'm thinking about adding it back on the bow just for the better DI image. JMO