Yes, the DFF1-UHD will work exactly the same on the TZT3 as it did with your existing TZT2. I am surprised you haven't seen any problems on the LF side because the B175L is rated for 40 to 60 Kz but the sounder is sweeping outside of that from 30-70. It isn't one of the rated transducers for that sounder. The 275 yes, but the 175 no. If you have been happy with it, it will be the same talking to the TZT3.