Reaper, it is my understanding all you need is the NEMA 2000 bus to connect to the Xi5?????? I'd be surprised if you could use the Xi5 with anything other than a Lowrance HDS but, am guessing any HDS with NEMA 2000 capability would work and you could use either the front or console HDS to control the TM.
I still have my MK Fortrex and will keep it till I get a ride with someone with an Xi5 before I write that check!