FYI, if a bow mounted TM is in the plans, only a Garmin FF can network with a Garmin TM. Birds network with Minkota. Lowrance networks with Motorguide. Other than that, it comes down to customer service. Garmin has a good rep for that. I have the 93svuhd with the GT56 (glorified GT54) and it is not the best ducer for trolling. I also fish SM and Pike and for that, it is very usefull. For trolling, I picked up a refurbished Lowrance with a basic 2d ducer 83/200 for less than the price of upgrading the ducer on the Garmin. And, it networks with my MG.