No matter what finder you choose to fit your price range/needs I'd suggest using Nextag online. They are really good at finding the cheapest deals, best deals out there. I just bought a hummingbird 587 for just over $400 that anywhere else would've cost me $450 easily. If I'd have waited I could've gotten it for just under $400 at around $380ish. You can look up much cheaper models there too so don't feel like you gotta buy a $400 unit. As for the ducer mounting to the T-motor that's a matter of zip ties and a cable clamp around the head of your T-motor, really easy to do.