I just pulled the trigger on a Lowrance Elite 4X DSI fish finder - Is DSI ok?

[Biggrizzly]

I read a number of reviews and I guess I was really confused in regard to the many different versions of the Elite 4 series fishfinders. I just realized that the 4X does not come with any GPS at all - which is really ok as I intended on using a handheld GPS or my Droid Razor which has the Navionics USA on it. Also, now considering that maybe DSI is too much detail, any thoughts on any of this. I also understand the DSI Xducer must be mounted outside of the Yak. Comments please