If you're having problems with the manufacturer, why would you want to buy more of their instruments? I would suggest voting with your wallet and going with a different manufacturer.
BTW, the wireless TackTick gear is pretty good. I installed it on my boat two seasons ago, and have been very happy with it. The fact that the only wiring is from the hull depth and speed transducers to the hull transmitter and power for the hull transmitter, makes the installation much simpler and allows you to add displays where ever you need them without a need to worry about wiring.
The T104 kit comes with the speed, depth/temp, and wind transducers, as well as the the hull transmitter, NMEA interface and two-line digital display and analog wind display.
A couple of nice things about the TackTick gear that you probably won't hear about.
First, the digital display can display the system voltage going into the hull transmitter. This can give you a quick check on your battery charge state...
Second, the hull transmitter has a small battery in it and can power the transducers for several hours without external power. This means even if your house battery bank dies, you will still have instruments for a while.
Third, the solar panels on the displays and the wind transducer are pretty efficient and once fully charged, they're good to go for about 250 hours without additional sunlight charging.
Fourth, you can mount the instrument displays on a port and still be able to open the port. That can maximize bulkhead space and use on a small boat. I did this because my boat is fairly small, and I wanted to install a port near the galley, on the port side of the cockpit bulkhead, and mounting the displays to it simplified things a lot.
Fifth, TackTick uses fairly standard Airmar transducers, and you may not need to replace your transducers. I had Raymarine ST60 gear in place originally, and I was able to use the Raymarine transducers with the TackTick hull transmitter. I will replace the transducers this winter. However, it allowed me to use the boat without hauling it to replace the transducers. The only reason I am replacing the transducers is that I am selling the Raymarine kit, and I like the TackTick version of the transducers better. The knotmeter through-hull has a flap that reduces water intrusion when switching the knotmeter out for the plug or cleaning.
