There is no telling how much Lowrance will charge for the transducer to upgrade the unit. Plus it's just a rumor.

I have a 797 and almost bought a 798 a month ago, but decided I didn't need 2 of them so I bought a 788 and interlink.

Not being much of a lowrance guy myself, I wouldn't buy the lowrance unless I could upgrade to the 7 inch screen, but without the SI, I don't think it's worth it.

I've been amazed at what Lowrance commands for their units, even though they don't have SI most of them are priced equivelant to the SI. I often wonder why anyone buys them. Now the GPS functionality is second to none, but a guy could just by a standalone gps unit.